U.S. patent application number 12/297596 was filed with the patent office on 2009-11-19 for isoxazole derivatives as calcium channel blockers.
Invention is credited to Richard Holland, Hassan Pajouhesh, Hossein Pajouhesh.
Application Number | 20090286806 12/297596 |
Document ID | / |
Family ID | 38609001 |
Filed Date | 2009-11-19 |
United States Patent
Application |
20090286806 |
Kind Code |
A1 |
Pajouhesh; Hassan ; et
al. |
November 19, 2009 |
ISOXAZOLE DERIVATIVES AS CALCIUM CHANNEL BLOCKERS
Abstract
Methods and compounds effective in ameliorating conditions
characterized by unwanted calcium channel activity, particularly
unwanted N-type or T-type calcium channel activity are disclosed.
Specifically, a series of isoxazole containing compounds are
disclosed of the general formula (1) where Z is N or CHNR.sup.3 and
(Ar.sup.1).sub.2CR.sup.4 is optionally substituted benzhydryl.
##STR00001##
Inventors: |
Pajouhesh; Hassan; (West
Vancouver, CA) ; Holland; Richard; (Vancouver,
CA) ; Pajouhesh; Hossein; (Coquitlam, CA) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
12531 HIGH BLUFF DRIVE, SUITE 100
SAN DIEGO
CA
92130-2040
US
|
Family ID: |
38609001 |
Appl. No.: |
12/297596 |
Filed: |
April 17, 2007 |
PCT Filed: |
April 17, 2007 |
PCT NO: |
PCT/CA07/00632 |
371 Date: |
June 24, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60792438 |
Apr 17, 2006 |
|
|
|
Current U.S.
Class: |
514/254.04 ;
544/367 |
Current CPC
Class: |
A61K 31/42 20130101;
A61K 31/496 20130101; C07D 261/08 20130101; C07D 295/03 20130101;
C07D 261/18 20130101; C07D 413/06 20130101 |
Class at
Publication: |
514/254.04 ;
544/367 |
International
Class: |
A61K 31/497 20060101
A61K031/497; C07D 413/06 20060101 C07D413/06 |
Claims
1. A method to treat a condition modulated by calcium ion channel
activity, which method comprises administering to a subject in need
of such treatment an amount of the compound of formula (1)
effective to ameliorate said condition, wherein said compound is of
the formula: ##STR00057## or a pharmaceutically acceptable salt or
conjugate thereof wherein Z is N or CHNR.sup.3; X.sup.1 is an
optionally substituted alkylene (1-8C), alkenylene (2-8C),
alkynylene (2-8C), heteroalkylene (2-8C), heteroalkenylene (2-8C),
or heteroalkynylene (2-8C); X is an optionally substituted alkylene
(1-2C); each Ar.sup.1 and Ar.sup.2 is independently an aromatic or
heteroaromatic ring and is optionally substituted; each R.sup.1 is
independently .dbd.O, halo, CN, OR', SR', SOR', SO.sub.2R',
NR'.sub.2, NR'(CO)R', or NR'SO.sub.2R', wherein each R' is
independently H or an optionally substituted group selected from
alkyl (1-6C), alkenyl (2-8C), alkynyl (2-8C), heteroalkyl (2-8C),
heteroalkenyl (2-8C), heteroalkynyl (2-8C), heteroaryl (5-12C), and
aryl (6-10C); or R.sup.1 may be an optionally substituted group
selected from alkyl (1-8C), alkenyl (2-8C), alkynyl (2-8C),
heteroalkyl (2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C),
aryl (6-1.degree. C.), heteroaryl (5-12C), O-aryl (6-1.degree. C.),
O-heteroaryl (5-12C) and C6-C12-aryl-C1-C8-alkyl; R is H, halo, CN,
NO.sub.2, CF.sub.3, COOR', CONR.sub.12, OR', SR', SOR', SO.sub.2R',
NR.sub.12, NR'(CO)R', or NR'SO.sub.2R', wherein each R' is
independently H or an optionally substituted group selected from
alkyl (1-6C), alkenyl (2-8C), alkynyl (2-8C), heteroalkyl (2-8C),
heteroalkenyl (2-8C), heteroalkynyl (2-8C), heteroaryl (5-12C), and
aryl (6-10C); or R.sup.2 may be an optionally substituted group
selected from alkyl (1-8C), alkenyl (2-8C), alkynyl (2-8C),
heteroalkyl (2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C),
aryl (6-10C), heteroaryl (5-12C), O-aryl (6-10C), O-heteroaryl
(5-12C) and C6-C12-aryl-C1-C8-alkyl; R.sup.3 is H, or an optionally
substituted group selected from alkyl (1-8C), alkenyl (2-8C) and
alkynyl (2-8C); R.sup.4 is H, OH, alkyl (1-4C), alkenyl (2-4C),
OR', C(O)R, CN, or Arl, wherein each R is optionally substituted
alkyl (1-4C); n is 0 or 1; m is 0-4, and wherein the optional
substituents for each Ar.sup.1 and Ar.sup.2 are independently
selected from the group consisting of halo, CN, NO.sub.2, CF.sub.3,
COOR', CONR.sub.12, OR', SR', SOR', SO.sub.2R', NR.sub.12,
NR'(CO)R', or NR'SO.sub.2R', wherein each R' is independently H or
an optionally substituted group selected from alkyl (1-6C), alkenyl
(2-8C), alkynyl (2-8C), heteroalkyl (2-8C), heteroalkenyl (2-8C),
heteroalkynyl (2-8C), heteroaryl (5-12C), and aryl (6-10C); or the
optional substituent may be an optionally substituted group
selected from alkyl (1-8C), alkenyl (2-8C), alkynyl (2-8C),
heteroalkyl (2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C),
aryl (6-1.degree. C.), heteroaryl (5-12C), O-aryl (6-1.degree. C.),
O-heteroaryl (5-12C) and C6-C12-aryl-C1-C8-alkyl.
2. The method of claim 1 wherein said condition is modulated by
N-type calcium channel activity.
3. The method of claim 1 wherein said condition is chronic or acute
pain, mood disorders, neurodegenerative disorders, gastrointestinal
disorders, genitorurinary disorders, neuroprotection, metabolic
disorders, cardiovascular disease, epilepsy, diabetes, prostate
cancer, sleep disorders, Parkinson's disease, schizophrenia or male
birth control.
4. The method of claim 3 wherein said condition is chronic or acute
pain.
5. The method of claim 1, wherein Z is N.
6. The method of claim 1, wherein (Ar.sup.1).sub.2CR.sup.4 is an
optionally substituted benzhydryl.
7. (canceled)
8. The method of claim 1, wherein n is 0.
9. The method of claim 1, wherein n is 1.
10. The method of claim 9 wherein X.sup.1 is an optionally
substituted alkylene (1-4C), alkenylene (2-4C), alkynylene (2-4C),
heteroalkylene (2-4C), heteroalkenylene (2-4C), or heteroalkynylene
(2-4C).
11. The method of claim 10 wherein X.sup.1 is an optionally
substituted alkylene (1-4C) or heteroalkylene (2-4C).
12. The method of claim 11 wherein X.sup.1 is an optionally
substituted heteroalkylene containing at least one of NH, O, S, SO,
and SO.sub.2.
13. The method of claim 12 wherein X.sup.1 is NHCH.sub.2CO,
OCH.sub.2CO, SCH.sub.2CO, SOCH.sub.2CO or SO.sub.2CH.sub.2CO.
14. (canceled)
15. The method of claim 10, wherein X.sup.1 is optionally
substituted alkylene (1-4C) substituted by .dbd.O.
16. The method of claim 15 wherein X.sup.1 is CH.sub.2CO.
17. The method of claim 1, wherein X.sup.2 is an optionally
substituted alkylene (1-4C) or heteroalkylene (1-4C).
18. The method of claim 17 wherein X.sup.2 is an optionally
substituted alkylene (1-2C)
19. (canceled)
20. The method of claim 18 wherein X.sup.2 is substituted by
.dbd.O.
21. The method of claim 18 wherein X.sup.2 is CH.sub.2 or CO.
22. The method of claim 18, wherein R.sup.4 is H.
23. The method of claim 1, wherein Ar.sup.2 is an optionally
substituted phenyl.
24. (canceled)
25. The method of claim 1, wherein the compound is:
(4-benzhydrylpiperazin-1-yl)(3-phenylisoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-phenylisoxazole;
(4-benzhydrylpiperazin-1-yl)(3-(2-fluorophenyl)isoxazol-5-yl)methanone;
(4-benzhydrylpiperazin-1-yl)(3-(2-methoxyphenyl)isoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-(2-methoxyphenyl)isoxazole;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-(2-fluorophenyl)isoxazole;
1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-dipheny-
lpropan-1-one;
1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-diphen-
ylpropan-1-one;
3,3-diphenyl-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1-yl)propan-1--
one;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-ph-
enylisoxazole;
(4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)(3-(2-fluorophenyl)-
isoxazol-5-yl)methanone;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-(2-flu-
orophenyl)isoxazole;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-(2-met-
hoxyphenyl)isoxazole;
5-((4-((2,4-dichlorophenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-phenyl-
isoxazole;
(4-((2,4-dichlorophenyl)(phenyl)methyl)piperazin-1-yl)(3-(2-flu-
orophenyl)isoxazol-5-yl)methanone;
5-((4-((2,4-dichlorophenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-(2-flu-
orophenyl) isoxazole;
2-(benzhydrylamino)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperaz-
in-1-yl)ethanone;
2-(benzhydryloxy)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazin-
-1-yl)ethanone;
2-(benzhydrylthio)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazi-
n-1-yl)ethanone;
2-(benzhydrylsulfinyl)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)pipe-
razin-1-yl)ethanone;
2-(benzhydrylamino)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)pipera-
zin-1-yl)ethanone;
2-(benzhydryloxy)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperazi-
n-1-yl)ethanone;
2-(benzhydrylthio)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperaz-
in-1-yl)ethanone;
2-(benzhydrylsulfinyl)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)pip-
erazin-1-yl)ethanone;
2-(benzhydrylamino)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1-yl)et-
hanone;
2-(benzhydryloxy)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1--
yl)ethanone;
2-(benzhydrylthio)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1-yl)eth-
anone;
2-(benzhydrylsulfinyl)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazi-
n-1-yl)ethanone;
2-(benzhydrylamino)-1-(4-(3-(2-methoxyphenyl)isoxazole-5-carbonyl)piperaz-
in-1-yl)ethanone; or a pharmaceutically acceptable salt of any of
these.
26. The method of claim 17 wherein the compound is:
(4-benzhydrylpiperazin-1-yl)(3-phenylisoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-phenylisoxazole;
(4-benzhydrylpiperazin-1-yl)(3-(2-fluorophenyl)isoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-(2-methoxyphenyl)isoxazole;
1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-dipheny-
lpropan-1-one;
1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-diphen-
ylpropan-1-one;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-phenyl-
isoxazole;
(4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)(3-(2-flu-
orophenyl)isoxazol-5-yl)methanone; or a pharmaceutically acceptable
salt of one of these.
27. A compound of the formula: ##STR00058## or a pharmaceutically
acceptable salt or conjugate thereof wherein Z is N or CHNR.sup.3;
X.sup.1 is an optionally substituted alkylene (1-8C), alkenylene
(2-8C), alkynylene (2-8C), heteroalkylene (2-8C), heteroalkenylene
(2-8C), or heteroalkynylene (2-8C); X.sup.2 is an optionally
substituted alkylene (1-2C); each Ar.sup.1 and Ar.sup.2 is
independently an aromatic or heteroaromatic ring and is optionally
substituted; each R.sup.1 is independently .dbd.O, halo, CN, OR',
SR', SOR', SO.sub.2R', NR.sub.12, NR'(CO)R', or NR'SO.sub.2R',
wherein each R' is independently H or an optionally substituted
group selected from alkyl (1-6C), alkenyl (2-8C), alkynyl (2-8C),
heteroalkyl (2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C),
heteroaryl (5-12C), and aryl (6-10C); or R.sup.1 may be an
optionally substituted group selected from alkyl (1-8C), alkenyl
(2-8C), alkynyl (2-8C), heteroalkyl (2-8C), heteroalkenyl (2-8C),
heteroalkynyl (2-8C), aryl (6-1.degree. C.), heteroaryl (5-12C),
O-aryl (6-1.degree. C.), O-heteroaryl (5-12C) and
C6-C12-aryl-C1-C8-alkyl; R.sup.2 is H, halo, CN, NO.sub.2,
CF.sub.3, COOR', CONR.sub.12, OR', SR', SOR', SO.sub.2R',
NR.sub.12, NR'(CO)R', or NR'SO.sub.2R', wherein each R.sup.1 is
independently H or an optionally substituted group selected from
alkyl (1-6C), alkenyl (2-8C), alkynyl (2-8C), heteroalkyl (2-8C),
heteroalkenyl (2-8C), heteroalkynyl (2-8C), heteroaryl (5-12C), and
aryl (6-10C); or R.sup.2 may be an optionally substituted group
selected from alkyl (1-8C), alkenyl (2-8C), alkynyl (2-8C),
heteroalkyl (2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C),
aryl (6-1.degree. C.), heteroaryl (5-12C), O-aryl (6-1.degree. C.),
O-heteroaryl (5-12C) and C6-C12-aryl-C1-C8-alkyl; R.sup.3 is H, or
an optionally substituted group selected from alkyl (1-8C), alkenyl
(2-8C) and alkynyl (2-8C); R.sup.4 is H, OH, alkyl (1-4C), alkenyl
(2-4C), OR', C(O)R, CN, or Ar.sup.1, wherein each R is optionally
substituted alkyl (1-4C); n is 1; m is 0-4, and wherein the
optional substituents for each Ar.sup.1 and Ar.sup.2 are
independently selected from the group consisting of halo, CN,
NO.sub.2, CF.sub.3, COOR', CONR.sub.12, OR', SR', SOR', SO.sub.2R',
NR.sub.12, NR'(CO)R', or NR'SO.sub.2R', wherein each R' is
independently H or an optionally substituted group selected from
alkyl (1-6C), alkenyl (2-8C), alkynyl (2-8C), heteroalkyl (2-8C),
heteroalkenyl (2-8C), heteroalkynyl (2-8C), heteroaryl (5-12C), and
aryl (6-10C); or the optional substituent may be an optionally
substituted group selected from alkyl (1-8C), alkenyl (2-8C),
alkynyl (2-8C), heteroalkyl (2-8C), heteroalkenyl (2-8C),
heteroalkynyl (2-8C), aryl (6-1.degree. C.), heteroaryl (5-12C),
O-aryl (6-10C), O-heteroaryl (5-12C) and
C6-C12-aryl-C1-C8-alkyl.
28. The compound of claim 27 wherein Z is N.
29. The compound of claim 27 wherein (Ar.sup.1).sub.2CR.sup.4 is an
optionally substituted benzhydryl.
30. (canceled)
31. The compound of claim 27 wherein n is 0.
32. (canceled)
33. The compound of claim 27, wherein X.sup.1 is an optionally
substituted alkylene (1-4C), alkenylene (2-4C), alkynylene (2-4C),
heteroalkylene (2-4C), heteroalkenylene (2-4C), or heteroalkynylene
(2-4C).
34. The compound of claim 33 wherein X.sup.1 is an optionally
substituted alkylene (1-4C) or heteroalkylene (2-4C).
35. The compound of claim 34 wherein X.sup.1 is an optionally
substituted heteroalkylene containing at least one of NH, O, S, SO,
and SO.sub.2.
36. The compound of claim 35 wherein X.sup.1 is NHCH.sub.2CO,
OCH.sub.2CO, SCH.sub.2CO, SOCH.sub.2CO or SO.sub.2CH.sub.2CO.
37. (canceled)
38. The compound of claim 27, wherein X.sup.1 is an optionally
substituted alkylene (1-4C) substituted by .dbd.O.
39. The compound of claim 38 wherein X.sup.1 is CH.sub.2CO.
40. The compound of claim 27 wherein X.sup.2 is an optionally
substituted alkylene (1-4C) or heteroalkylene (1-4C).
41. The compound of claim 40, wherein X.sup.2 is an optionally
substituted alkylene (1-2C)
42. The compound of claim 41, wherein X.sup.2 is unsubstituted.
43. The compound of claim 41, wherein X.sup.2 is substituted by
.dbd.O.
44. The compound of claim 41, wherein X.sup.2 is CH.sub.2 or
CO.
45. The compound of claim 41, wherein R.sup.4 is H.
46. The compound of claim 27, wherein Ar.sup.2 is an optionally
substituted phenyl.
47. The compound of claim 45 wherein Ar.sup.2 is an unsubstituted
phenyl.
48. The compound of claim 27 wherein the compound is:
(4-benzhydrylpiperazin-1-yl)(3-phenylisoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-phenylisoxazole;
(4-benzhydrylpiperazin-1-yl)(3-(2-fluorophenyl)isoxazol-5-yl)methanone;
(4-benzhydrylpiperazin-1-yl)(3-(2-methoxyphenyl)isoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-(2-methoxyphenyl)isoxazole;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-(2-fluorophenyl)isoxazole;
1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-dipheny-
lpropan-1-one;
1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-diphen-
ylpropan-1-one;
3,3-diphenyl-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1-yl)propan-1--
one;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-ph-
enylisoxazole;
(4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)(3-(2-fluorophenyl)-
isoxazol-5-yl)methanone;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-(2-flu-
orophenyl)isoxazole;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-(2-met-
hoxyphenyl)isoxazole;
5-((4-((2,4-dichlorophenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-phenyl-
isoxazole;
(4-((2,4-dichlorophenyl)(phenyl)methyl)piperazin-1-yl)(3-(2-flu-
orophenyl)isoxazol-5-yl)methanone;
5-((4-((2,4-dichlorophenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-(2-flu-
orophenyl) isoxazole;
2-(benzhydrylamino)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperaz-
in-1-yl)ethanone;
2-(benzhydryloxy)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazin-
-1-yl)ethanone;
2-(benzhydrylthio)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazi-
n-1-yl)ethanone;
2-(benzhydrylsulfinyl)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)pipe-
razin-1-yl)ethanone;
2-(benzhydrylamino)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)pipera-
zin-1-yl)ethanone;
2-(benzhydryloxy)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperazi-
n-1-yl)ethanone;
2-(benzhydrylthio)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperaz-
in-1-yl)ethanone;
2-(benzhydrylsulfinyl)-1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)pip-
erazin-1-yl)ethanone;
2-(benzhydrylamino)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1-yl)et-
hanone;
2-(benzhydryloxy)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1--
yl)ethanone;
2-(benzhydrylthio)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazin-1-yl)eth-
anone;
2-(benzhydrylsulfinyl)-1-(4-((3-phenylisoxazol-5-yl)methyl)piperazi-
n-1-yl)ethanone;
2-(benzhydrylamino)-1-(4-(3-(2-methoxyphenyl)isoxazole-5-carbonyl)piperaz-
in-1-yl)ethanone; or a pharmaceutically acceptable salt of any of
these.
49. The compound of claim 46 wherein the compound is:
(4-benzhydrylpiperazin-1-yl)(3-phenylisoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-phenylisoxazole;
(4-benzhydrylpiperazin-1-yl)(3-(2-fluorophenyl)isoxazol-5-yl)methanone;
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-(2-methoxyphenyl)isoxazole;
1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-dipheny-
lpropan-1-one;
1-(4-((3-(2-methoxyphenyl)isoxazol-5-yl)methyl)piperazin-1-yl)-3,3-diphen-
ylpropan-1-one;
5-((4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)methyl)-3-phenyl-
isoxazole;
(4-((2,4-dimethylphenyl)(phenyl)methyl)piperazin-1-yl)(3-(2-flu-
orophenyl)isoxazol-5-yl)methanone; or a pharmaceutically acceptable
salt of one of these.
50. A pharmaceutical composition which comprises the compound of
claim 27 in admixture with a pharmaceutically acceptable excipient.
Description
TECHNICAL FIELD
[0001] The invention relates to compounds useful in treating
conditions associated with calcium channel function, and
particularly conditions associated with N-type and/or T-type
calcium channel activity. More specifically, the invention concerns
compounds containing isoxazole derivatives that are useful in
treatment of conditions such as stroke and pain.
BACKGROUND ART
[0002] The entry of calcium into cells through voltage-gated
calcium channels mediates a wide variety of cellular and
physiological responses, including excitation-contraction coupling,
hormone secretion and gene expression (Miller, R. J., Science
(1987) 235:46-52; Augustine, G. J. et al., Annu Rev Neurosci (1987)
10: 633-693). In neurons, calcium channels directly affect membrane
potential and contribute to electrical properties such as
excitability, repetitive firing patterns and pacemaker activity.
Calcium entry further affects neuronal functions by directly
regulating calcium-dependent ion channels and modulating the
activity of calcium-dependent enzymes such as protein kinase C and
calmodulin-dependent protein kinase TI. An increase in calcium
concentration at the presynaptic nerve terminal triggers the
release of neurotransmitter and calcium channels, which also
affects neurite outgrowth and growth cone migration in developing
neurons.
[0003] Calcium channels mediate a variety of normal physiological
functions, and are also implicated in a number of human disorders.
Examples of calcium-mediated human disorders include but are not
limited to congenital migraine, cerebellar ataxia, angina,
epilepsy, hypertension, ischemia, and some arrhythmias. The
clinical treatment of some of these disorders has been aided by the
development of therapeutic calcium channel antagonists (e.g.,
dihydropyridines, phenylalkyl amines, and benzothiazapines all
target L-type calcium channels) (Janis, R. J. & Triggle, D. J.,
In Calcium Channels: Their Properties, Functions, Regulation and
Clinical Relevance (1991) CRC Press, London).
[0004] Native calcium channels have been classified by their
electrophysiological and pharmacological properties into T-, L-,
N-, P/Q- and R-types (reviewed in Catterall, W., Annu Rev Cell Dev
Biol (2000) 16: 521-555; Huguenard, J. R., Annu Rev Physiol (1996)
58: 329-348). T-type (or low voltage-activated) channels describe a
broad class of molecules that transiently activate at negative
potentials and are highly sensitive to changes in resting
potential.
[0005] The L-, N- and P/Q-type channels activate at more positive
potentials (high voltage-activated) and display diverse kinetics
and voltage-dependent properties (Catterall (2000); Huguenard
(1996)). L-type channels can be distinguished by their sensitivity
to several classes of small organic molecules used therapeutically,
including dihydropyridines (DHP's), phenylalkylamines and
benzothiazepines. In contrast, N-type and P/Q-type channels are
high affinity targets for certain peptide toxins produced by
venomous spiders and marine snails: N-type channels are blocked by
the .omega.-conopeptides .omega.-conotoxin GVIA (.omega.-CTx-GVIA)
isolated from Conus geographus and co-conotoxin MVIIA
(.omega.-CTx-MVIIA) isolated from Conus magus, while P/Q-type
channels are resistant to .omega.-CTx-MVIIA but are sensitive to
the funnel web spider peptide, .omega.-agatoxin IVA
(.omega.-Aga-IVA). R-type calcium channels are sensitive to block
by the tarantula toxin, SNX-482.
[0006] Neuronal high voltage-activated calcium channels are
composed of a large (>200 kDa) pore-forming .alpha..sub.1
subunit that is the target of identified pharmacological agents, a
cytoplasmically localized .about.50-70 kDa D subunit that tightly
binds the .alpha..sub.1 subunit and modulates channel biophysical
properties, and an .about.170 kDa .alpha..sub.2.delta. subunit
(reviewed by Stea, et al., Proc Natl Acad Sci USA (1994)
91:10576-10580; Catterall (2000)). At the molecular level, nine
different .alpha..sub.1 subunit genes expressed in the nervous
system have been identified and shown to encode all of the major
classes of native calcium currents (Table 1).
TABLE-US-00001 TABLE 1 Classification of Neuronal Calcium Channels
Gene .omega.-AGA .omega.-CTx .omega.-CTx dihydro- Native Class cDNA
Name IVA GVIA MVIA pyridines P/Q-type .alpha..sub.1A Ca.sub.v2.1 --
-- -- N-type .alpha..sub.1B Ca.sub.v2.2 -- -- L-type .alpha..sub.1C
Ca.sub.v1.2 -- -- -- L-type .alpha..sub.1D Ca.sub.v1.3 -- -- --
R-type .alpha..sub.1E Ca.sub.v2.3 -- -- -- -- L-type .alpha..sub.1F
Ca.sub.v1.4 -- -- -- T-type .alpha..sub.1G Ca.sub.v3.1 -- -- -- --
T-type .alpha..sub.1H Ca.sub.v3.2 -- -- -- -- T-type .alpha..sub.1I
Ca.sub.v3.3 -- -- -- --
[0007] Calcium channels have been shown to mediate the development
and maintenance of the neuronal sensitization processes associated
with neuropathic pain, and provide attractive targets for the
development of analgesic drugs (reviewed in Vanegas, H. &
Schaible, H-G., Pain (2000) 85: 9-18). All of the high-threshold Ca
channel types are expressed in the spinal cord, and the
contributions of L-, N and P/Q-types in acute nociception are
currently being investigated. In contrast, examination of the
functional roles of these channels in more chronic pain conditions
strongly indicates a pathophysiological role for the N-type channel
(reviewed in Vanegas & Schaible (2000) supra).
[0008] Mutations in calcium channel .alpha..sub.1 subunit genes in
animals can provide important clues to potential therapeutic
targets for pain intervention. Genetically altered mice null for
the .alpha..sub.1B N-type calcium channel gene have been reported
by several independent groups (Ino, M. et al., Proc Natl Acad Sci
USA (2001) 98(9): 5323-5328; Kim, C. et al., Mol Cell Neurosci
(2001) 18(2): 235-245; Saegusa, H. et al., Proc Natl Acad Sci USA
(2001) 97: 6132-6137; Hatakeyama, S. et al., Neuroreport (2001)
12(11): 2423-2427). The .alpha..sub.1B N-type null mice were
viable, fertile and showed normal motor coordination. In one study,
peripheral body temperature, blood pressure and heart rate in the
N-type gene knock-out mice were all normal (Saegusa, et al.
(2001)). In another study, the baroreflex mediated by the
sympathetic nervous system was reduced after bilateral carotid
occlusion (Ino, et al. (2001)). In another study, mice were
examined for other behavioral changes and were found to be normal
except for exhibiting significantly lower anxiety-related behaviors
(Saegusa, et al. (2001)), suggesting the N-type channel may be a
potential target for mood disorders as well as pain. In all
studies, mice lacking functional N-type channels exhibit marked
decreases in the chronic and inflammatory pain responses. In
contrast, mice lacking N-type channels generally showed normal
acute nociceptive responses.
[0009] Two examples of either FDA-approved or investigational drug
that act on N-type channel are gabapentin and ziconotide.
Gabapentin, 1-(aminomethyl)cyclohexaneacetic acid (Neurontin.RTM.),
is an anticonvulsant originally found to be active in a number of
animal seizure models (Taylor, C. P. et al., Epilepsy Res (1998)
29: 233-249). Subsequent work has demonstrated that gabapentin is
also successful at preventing hyperalgesia in a number of different
animal pain models, including chronic constriction injury (CCl),
heat hyperalgesia, inflammation, diabetic neuropathy, static and
dynamic mechanoallodynia associated with postoperative pain
(Taylor, et al. (1998); Cesena, R. M. & Calcutt, N. A.,
Neurosci Lett (1999) 262: 101-104; Field, M. J. et al., Pain (1999)
80: 391-398; Cheng, J-K., et al., Anesthesiology (2000) 92:
1126-1131; Nicholson, B., Acta Neurol Scand (2000) 101:
359-371).
[0010] While its mechanism of action is not completely understood,
current evidence suggests that gabapentin does not directly
interact with GABA receptors in many neuronal systems, but rather
modulates the activity of high threshold calcium channels.
Gabapentin has been shown to bind to the calcium channel
.alpha..sub.2.delta. ancillary subunit, although it remains to be
determined whether this interaction accounts for its therapeutic
effects in neuropathic pain.
[0011] In humans, gabapentin exhibits clinically effective
anti-hyperalgesic activity against a wide ranging of neuropathic
pain conditions. Numerous open label case studies and three large
double blind trials suggest gabapentin might be useful in the
treatment of pain. Doses ranging from 300-2400 mg/day were studied
in treating diabetic neuropathy (Backonja, M. et al., JAMA (1998)
280:1831-1836), postherpetic neuralgia (Rowbotham, M. et al., JAMA
(1998) 280: 1837-1842), trigeminal neuralgia, migraine and pain
associated with cancer and multiple sclerosis (Di Trapini, G. et
al., Clin Ter (2000) 151: 145-148; Caraceni, A. et al., J Pain
& Symp Manag (1999) 17: 441-445; Houtchens, M. K. et al.,
Multiple Sclerosis (1997) 3: 250-253; see also Magnus, L.,
Epilepsia (1999) 40(Suppl 6): S66-S72; Laird, M. A. & Gidal, B.
E., Annal Pharmacotherap (2000) 34: 802-807; Nicholson, B., Acta
Neurol Scand (2000) 101: 359-371).
[0012] Ziconotide (Prialt.RTM.; SNX-111) is a synthetic analgesic
derived from the cone snail peptide Conus magus MVIIA that has been
shown to reversibly block N-type calcium channels. In a variety of
animal models, the selective block of N-type channels via
intrathecal administration of Ziconotide significantly depresses
the formalin phase 2 response, thermal hyperalgesia, mechanical
allodynia and post-surgical pain (Malmberg, A. B. & Yaksh, T.
L., J Neurosci (1994) 14: 4882-4890; Bowersox, S. S. et al., J
Pharmacol Exp Ther (1996) 279: 1243-1249; Sluka, K. A., J Pharmacol
Exp Ther (1998) 287:232-237; Wang, Y-X. et al., Soc Neurosci Abstr
(1998) 24: 1626).
[0013] Ziconotide has been evaluated in a number of clinical trials
via intrathecal administration for the treatment of a variety of
conditions including post-herpetic neuralgia, phantom limb
syndrome, HIV-related neuropathic pain and intractable cancer pain
(reviewed in Mathur, V. S., Seminars in Anesthesia, Perioperative
medicine and Pain (2000) 19: 67-75). In phase II and III clinical
trials with patients unresponsive to intrathecal opiates,
Ziconotide has significantly reduced pain scores and in a number of
specific instances resulted in relief after many years of
continuous pain. Ziconotide is also being examined for the
management of severe post-operative pain as well as for brain
damage following stroke and severe head trauma (Heading, C., Curr
Opin CPNS Investigational Drugs (1999) 1: 153-166). In two case
studies Ziconotide has been further examined for usefulness in the
management of intractable spasticity following spinal cord injury
in patients unresponsive to baclofen and morphine (Ridgeway, B. et
al., Pain (2000) 85: 287-289). In one instance Ziconotide decreased
the spasticity from the severe range to the mild to none range with
few side effects. In another patient Ziconotide also reduced
spasticity to the mild range although at the required dosage
significant side effects including memory loss, confusion and
sedation prevented continuation of the therapy.
[0014] T-type calcium channels are involved in various medical
conditions. In mice lacking the gene expressing the .alpha..sub.1G
subunit, resistance to absence seizures was observed (Kim, C. et
al., Mol Cell Neurosci (2001) 18(2): 235-245). Other studies have
also implicated the .alpha..sub.1H subunit in the development of
epilepsy (Su, H. et al., J Neurosci (2002) 22: 3645-3655). There is
strong evidence that some existing anticonvulsant drugs, such as
ethosuximide, function through the blockade of T-type channels
(Gomora, J. C. et al., Mol Pharmacol (2001) 60: 1121-1132).
[0015] Low voltage-activated calcium channels are highly expressed
in tissues of the cardiovascular system. Mibefradil, a calcium
channel blocker 10-30-fold selective for T-type over L-type
channels, was approved for use in hypertension and angina. It was
withdrawn from the market shortly after launch due to interactions
with other drugs (Heady, T. N., et al., Jpn J Pharmacol. (2001)
85:339-350).
[0016] Growing evidence suggests T-type calcium channels may also
be involved in pain. Both mibefradil and ethosuximide have shown
anti-hyperalgesic activity in the spinal nerve ligation model of
neuropathic pain in rats (Dogrul, A., et al., Pain (2003)
105:159-168).
[0017] U.S. Pat. Nos. 6,011,035; 6,294,533; 6,310,059; and
6,492,375; PCT publications WO 01375 and WO 01/45709; PCT
publications based on PCT CA 99/00612, PCT CA 00/01586; PCT CA
00/01558; PCT CA 00/01557; PCT CA 2004/000535; and PCT CA
2004/000539, and U.S. patent application Ser. Nos. 10/746,932 filed
23 Dec. 2003; 10/746,933 filed 23 Dec. 2003; 10/409,793 filed 8
Apr. 2003; 10/409,868 filed 8 Apr. 2003; 10/655,393 filed 3 Sep.
2003; 10/821,584 filed 9 Apr. 2004; and 10/821,389 filed 9 Apr.
2004 disclose calcium channel blockers where a piperidine or
piperazine ring is substituted by various aromatic moieties.
[0018] U.S. Pat. No. 5,646,149 describes calcium channel
antagonists of the formula A-Y-B wherein B contains a piperazine or
piperidine ring directly linked to Y. An essential component of
these molecules is represented by A, which must be an antioxidant;
the piperazine or piperidine itself is said to be important. The
exemplified compounds contain a benzhydryl substituent, based on
known calcium channel blockers (see below). U.S. Pat. No. 5,703,071
discloses compounds said to be useful in treating ischemic
diseases. A mandatory portion of the molecule is a tropolone
residue, with substituents such as piperazine derivatives,
including their benzhydryl derivatives. U.S. Pat. No. 5,428,038
discloses compounds indicated to exhibit a neural protective and
antiallergic effect. These compounds are coumarin derivatives which
may include derivatives of piperazine and other six-membered
heterocycles. A permitted substituent on the heterocycle is
diphenylhydroxymethyl. U.S. Pat. No. 6,458,781 describes 79 amides
as calcium channel antagonists though only a couple of which
contain both piperazine rings and benzhydryl moieties. Thus,
approaches in the art for various indications which may involve
calcium channel blocking activity have employed compounds which
incidentally contain piperidine or piperazine moieties substituted
with benzhydryl but mandate additional substituents to maintain
functionality.
[0019] Certain compounds containing both benzhydryl moieties and
piperidine or piperazine are known to be calcium channel
antagonists and neuroleptic drugs. For example, Gould, R. J., et
al., Proc Natl Acad Sci USA (1983) 80:5122-5125 describes
antischizophrenic neuroleptic drugs such as lidoflazine,
fluspirilene, pimozide, clopimozide, and penfluridol. It has also
been shown that fluspirilene binds to sites on L-type calcium
channels (King, V. K., et al., J Biol Chem (1989) 264:5633-5641) as
well as blocking N-type calcium current (Grantham, C. J., et al.,
Brit J Pharmacol (1944) 111:483-488). In addition, Lomerizine, as
developed by Kanebo, K. K., is a known calcium channel blocker.
However, Lomerizine is not specific for N-type channels. A review
of publications concerning Lomerizine is found in Dooley, D.,
Current Opinion in CPNS Investigational Drugs (1999) 1:116-125.
[0020] All patents, patent applications and publications are herein
incorporated by reference in their entirety.
DISCLOSURE OF THE INVENTION
[0021] The invention relates to compounds useful in treating
conditions modulated by calcium channel activity and in particular
conditions mediated by N-type and/or T-type calcium channel
activity. The compounds of the invention are isoxazole containing
compounds with substituents that enhance the calcium channel
blocking activity of the compounds. Thus, in one aspect, the
invention is directed to a method of treating conditions mediated
by calcium channel activity by administering to patients in need of
treatment compounds of the formula
##STR00002##
[0022] and pharmaceutically acceptable salts or conjugates
thereof
[0023] wherein Z is N or CHNR.sup.3;
[0024] X.sup.1 is an optionally substituted alkylene (1-8C),
alkenylene (2-8C), alkynylene (2-8C), heteroalkylene (2-8C),
heteroalkenylene (2-8C), or heteroalkynylene (2-8C);
[0025] X.sup.2 is an optionally substituted alkylene (1-2C);
[0026] each Ar.sup.1 and Ar.sup.2 is independently an aromatic or
heteroaromatic ring and is optionally substituted;
[0027] each R' is independently .dbd.O, halo, CN, OR', SR', SOR',
SO.sub.2R', NR.sub.12, NR'(CO)R', or NR'SO.sub.2R', wherein each R'
is independently H or an optionally substituted group selected from
alkyl (1-6C), alkenyl (2-8C), alkynyl (2-8C), heteroalkyl (2-8C),
heteroalkenyl (2-8C), heteroalkynyl (2-8C), heteroaryl (5-12C), and
aryl (6-10C); or R.sup.1 may be an optionally substituted group
selected from alkyl (1-8C), alkenyl (2-8C), alkynyl (2-8C),
heteroalkyl (2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C),
aryl (6-1.degree. C.), heteroaryl (5-12C), O-aryl (6-10C),
O-heteroaryl (5-12C) and C6-C12-aryl-C1-C8-alkyl;
[0028] R.sub.2 is H, halo, CN, NO.sub.2, CF.sub.3, COOR',
CONR.sub.12, OR', SR', SOR', SO.sub.2R', NR.sub.12, NR'(CO)R', or
NR'SO.sub.2R', wherein each R.sup.1 is independently H or an
optionally substituted group selected from alkyl (1-6C), alkenyl
(2-8C), alkynyl (2-8C), heteroalkyl (2-8C), heteroalkenyl (2-8C),
heteroalkynyl (2-8C), heteroaryl (5-12C), and aryl (6-1.degree.
C.); or R.sup.2 may be an optionally substituted group selected
from alkyl (1-8C), alkenyl (2-8C), alkynyl (2-8C), heteroalkyl
(2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C), aryl
(6-1.degree. C.), heteroaryl (5-12C), O-aryl (6-10C), O-heteroaryl
(5-12C) and C6-C12-aryl-C1-C8-alkyl;
[0029] R.sup.3 is H, or an optionally substituted group selected
from alkyl (1-8C), alkenyl (2-8C) and alkynyl (2-8C);
[0030] R.sup.4 is H, OH, alkyl (1-4C), alkenyl (2-4C), OR', C(O)R',
CN, or Ar.sup.1, wherein each R is optionally substituted alkyl
(1-4C);
[0031] n is 0 or 1;
[0032] m is 0-4, and
[0033] wherein the optional substituents for each Ar.sup.1 and
Ar.sup.2 are independently selected from the group consisting of
halo, CN, NO.sub.2, CF.sub.3, COOR', CONR.sub.12, OR', SR', SOR',
SO.sub.2R', NR.sub.12, NR'(CO)R', or NR'SO.sub.2R', wherein each R'
is independently H or an optionally substituted group selected from
alkyl (1-6C), alkenyl (2-8C), alkynyl (2-8C), heteroalkyl (2-8C),
heteroalkenyl (2-8C), heteroalkynyl (2-8C), heteroaryl (5-12C), and
aryl (6-10C); or the optional substituent may be an optionally
substituted group selected from alkyl (1-8C), alkenyl (2-8C),
alkynyl (2-8C), heteroalkyl (2-SC), heteroalkenyl (2-8C),
heteroalkynyl (2-8C), aryl (6-1.degree. C.), heteroaryl (5-12C),
O-aryl (6-10C), O-heteroaryl (5-12C) and
C6-C12-aryl-C1-C8-alkyl.
[0034] The invention is also directed to compounds of formula (I)
useful to modulate calcium channel activity, particularly N-type
and T-type channel activity, and to methods of treating such
conditions with these compounds. The invention is also directed to
the use of these compounds for the preparation of medicaments for
the treatment of conditions requiring modulation of calcium channel
activity, and in particular N-type calcium channel activity. In
another aspect, the invention is directed to pharmaceutical
compositions containing the compounds of formula (1) and to the use
of these compositions for treating conditions requiring modulation
of calcium channel activity, and particularly N-type calcium
channel activity.
DEFINITIONS
[0035] As used herein, the term "alkyl," "alkenyl" and "alkynyl"
include straight-chain, branched-chain and cyclic monovalent
substituents, as well as combinations of these, containing only C
and H when unsubstituted. Examples include methyl, ethyl, isobutyl,
cyclohexyl, cyclopentylethyl, 2-propenyl, 3-butynyl, and the like.
Typically, the alkyl, alkenyl and alkynyl groups contain 1-8C
(alkyl) or 2-8C (alkenyl or alkynyl). In some embodiments, they
contain 1-6C or 1-4C or 1-2C (alkyl); or 2-6C or 2-4C (alkenyl or
alkynyl). Further, any hydrogen atom on one of these groups can be
replaced with a halogen atom, and in particular a fluoro or chloro,
and still be within the scope of the definition of alkyl, alkenyl
and alkynyl. For example, CF.sub.3 is a 1C alkyl. These groups may
be also be substituted by other substituents.
[0036] Heteroalkyl, heteroalkenyl and heteroalkynyl are similarly
defined and contain at least one carbon atom but also contain one
or more O, S or N heteroatoms or combinations thereof within the
backbone residue whereby each heteroatom in the heteroalkyl,
heteroalkenyl or heteroalkynyl group replaces one carbon atom of
the alkyl, alkenyl or alkynyl group to which the heteroform
corresponds. In preferred embodiments, the heteroalkyl,
heteroalkenyl and heteroalkynyl groups have C at each terminus to
which the group is attached to other groups, and the heteroatom(s)
present are not located at a terminal position. As is understood in
the art, these heteroforms do not contain more than three
contiguous heteroatoms. In preferred embodiments, the heteroatom is
O or N. For greater certainty, to the extent that alkyl is defined
as 1-8C, then the corresponding heteroalkyl contains 2-8 C, N, O,
or S atoms such that the heteroalkyl contains at least one C atom
and at least one heteroatom. Similarly, when alkyl is defined as
1-6C or 1-4C, the heteroform would be 2-6C or 2-4C respectively,
wherein one C is replaced by O, N or S. Accordingly, when alkenyl
or alkynyl is defined as 2-8C (or 2-6C or 2-4C), then the
corresponding heteroform would also contain 2-8 C, N, O, or S atoms
(or 2-6 or 2-4 respectively) since the heteroalkenyl or
heteroalkynyl contains at least one carbon atom and at least one
heteroatom. Further, heteroalkyl, heteroalkenyl or heteroalkynyl
substituents may also contain one or more carbonyl groups. Examples
of heteroalkyl, heteroalkenyl and heteroalkynyl substituents
include CH.sub.2OCH.sub.3, CH.sub.2N(CH.sub.3).sub.2, CH.sub.2OH,
(CH.sub.2).sub.nNR.sub.2, OR', COOR', CONR.sub.2, (CH.sub.2).sub.n
OR', (CH.sub.2).sub.n COR', (CH.sub.2).sub.nCOOR',
(CH.sub.2).sub.nSR, (CH.sub.2).sub.nSOR',
(CH.sub.2).sub.nSO.sub.2R, (CH.sub.2).sub.nCONR.sub.2, NRCOR',
NRCOOR', OCONR.sub.2, OCOR and the like wherein the substituent
contains at least one C and the size of the substituent is
consistent with the definition of alkyl, alkenyl and alkynyl.
[0037] As used herein, the term "alkylene," "alkenylene" and
"alkynylene" refers to divalent groups having a specified size,
typically 1-4C or 1-8C for the saturated groups and 2-4C or 2-6C or
2-8 C for the unsaturated groups. They include straight-chain,
branched-chain and cyclic forms as well as combinations of these,
containing only C and H when unsubstituted. Because they are
divalent, they can link together two parts of a molecule, as
exemplified by X.sup.1 and X.sup.2 in formula (I). Examples include
methylene, ethylene, propylene, cyclopropan-1,1-diyl, ethylidene,
2-butene-1,4-diyl, and the like. These groups can be substituted by
the groups typically suitable as substituents for alkyl, alkenyl
and alkynyl groups as set forth herein. Thus C.dbd.O is a Cl
alkylene that is substituted by .dbd.O, for example.
[0038] Heteroalkylene, heteroalkenylene and heteroalkynylene are
similarly defined as divalent groups having a specified size,
typically 1-4C or 1-8C for the saturated groups and 2-4C or 2-6C or
2-8 C for the unsaturated groups. They include straight chain,
branched chain and cyclic groups as well as combinations of these,
and they further contain at least one carbon atom but also contain
one or more O, S or N heteroatoms or combinations thereof within
the backbone residue, whereby each heteroatom in the
heteroalkylene, heteroalkenylene or heteroalkynylene group replaces
one carbon atom of the alkyl, alkenyl or alkynyl group to which the
heteroform corresponds. As is understood in the art, these
heteroforms do not contain more than three contiguous
heteroatoms.
[0039] "Aromatic" moiety or "aryl" moiety refers to any monocyclic
or fused ring bicyclic system which has the characteristics of
aromaticity in terms of electron distribution throughout the ring
system and includes a monocyclic or fused bicyclic moiety such as
phenyl or naphthyl; "heteroaromatic" or "heteroaryl" also refers to
such monocyclic or fused bicyclic ring systems containing one or
more heteroatoms selected from O, S and N. The inclusion of a
heteroatom permits inclusion of 5-membered rings to be considered
aromatic as well as 6-membered rings. Thus, typical
aromatic/heteroaromatic systems include pyridyl, pyrimidyl,
indolyl, benzimidazolyl, benzotriazolyl, isoquinolyl, quinolyl,
benzothiazolyl, benzofuranyl, thienyl, furyl, pyrrolyl, thiazolyl,
oxazolyl, imidazolyl and the like. Because tautomers are
theoretically possible, phthalimido is also considered aromatic.
Typically, the ring systems contain 5-12 ring member atoms or 6-10
ring member atoms. In some embodiments, the aromatic or
heteroaromatic moiety is a 6-membered aromatic rings system
optionally containing 1-2 nitrogen atoms. More particularly, the
moiety is an optionally substituted phenyl, 2-, 3- or 4-pyridyl,
indolyl, 2- or 4-pyrimidyl, pyridazinyl, benzothiazolyl or
benzimidazolyl. Even more particularly, such moiety is phenyl,
pyridyl, or pyrimidyl and even more particularly, it is phenyl.
[0040] "O-aryl" or "O-heteroaryl" refers to aromatic or
heteroaromatic systems which are coupled to another residue through
an oxygen atom. A typical example of an O-aryl is phenoxy.
Similarly, "arylalkyl" refers to aromatic and heteroaromatic
systems which are coupled to another residue through a carbon
chain, saturated or unsaturated, typically of 1-8C or more
particularly 1-6C or 1-4C when saturated or 2-8C, 2-6C or 2-4C when
unsaturated, including the heteroforms thereof. For greater
certainty, arylalkyl thus includes an aryl or heteroaryl group as
defined above connected to an alkyl, heteroalkyl, alkenyl,
heteroalkenyl, alkynyl or heteroalkynyl moiety also as defined
above. Typical arylalkyls would be an aryl(6-12C)alkyl(1-8C),
aryl(6-12C)alkenyl(2-8C), or aryl(6-12C)alkynyl(2-8C), plus the
heteroforms. A typical example is phenylmethyl, commonly referred
to as benzyl.
[0041] Typical optional substituents on aromatic or heteroaromatic
groups include independently halo, CN, NO.sub.2, CF.sub.3, COOR',
CONR.sub.12, OR', SR', SOR', SO.sub.2R', NR.sub.12, NR'(CO)R', or
NR'SO.sub.2R', wherein each R' is independently H or an optionally
substituted group selected from alkyl (1-6C), heteroaryl (5-12C),
and aryl (6-1.degree. C.); or the substituent may be an optionally
substituted group selected from alkyl (1-8C), alkenyl (2-8C),
alkynyl (2-8C), heteroalkyl (2-8C), heteroalkenyl (2-8C),
heteroalkynyl (2-8C), aryl (6-10C), heteroaryl (5-12C), O-aryl
(6-10C), O-heteroaryl (5-12C) and C6-C12-aryl-C1-C8-alkyl.
[0042] Optional substituents on a non-aromatic group are typically
selected from =.dbd.O, .dbd.NOR', halo, CN, OR', SR', SOR',
SO.sub.2R', NR.sub.12, NR'(CO)R', or NR'SO.sub.2R', wherein each R'
is independently H or an optionally substituted group selected from
alkyl (1-6C), heteroaryl (5-12C), and aryl (6-10C); or it may be
alkyl (1-8C), alkenyl (2-8C), or alkynyl (2-8C), heteroalkyl
(2-8C), heteroalkenyl (2-8C), heteroalkynyl (2-8C), aryl (6-10C),
heteroaryl (5-12C), O-aryl (5-10C), O-heteroaryl (5-12C) and
C6-C12-aryl-C1-C8-alkyl. For greater certainty, two substituents on
the same N or adjacent C can form a 5-7 membered ring which may
contain one or two additional heteroatoms selected from N, O and
S.
[0043] Halo may be any halogen atom, especially F, Cl, Br, or I,
and more particularly it is fluoro or chloro.
[0044] In general, any alkyl, alkenyl, alkynyl, or aryl (including
all heteroforms defined above) group contained in a substituent may
itself optionally be substituted by additional substituents. The
nature of these substituents is similar to those recited with
regard to the substituents on the basic structures above. Thus,
where an embodiment of a substituent is alkyl, this alkyl may
optionally be substituted by the remaining substituents listed as
substituents where this makes chemical sense, and where this does
not undermine the size limit of alkyl per se; e.g., alkyl
substituted by alkyl or by alkenyl would simply extend the upper
limit of carbon atoms for these embodiments, and is not included.
However, alkyl substituted by aryl, amino, halo and the like would
be included.
[0045] There may be from 0-4 substituents (defined as R.sup.1) on
the central piperazine or piperidine ring and more particularly 0-2
substituents. Each R.sup.1 may independently be .dbd.O, alkyl,
alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, aryl,
heteroaryl, alkylaryl, O-aryl, O-heteroaryl, halo, CN, OH,
NO.sub.2, or NH.sub.2. Where it makes sense chemically, each of
these groups (other than H) can be substituted. In more particular
embodiments, R' may be 1-8C alkyl or heteroalkyl, more particularly
a 1-6C alkyl or heteroalkyl or a 1-4C alkyl or heteroalkyl. For
example, R.sup.1 may be CH.sub.3, CH.sub.2OH, CH.sub.2OCH.sub.3,
CH.sub.2OCH.sub.2COOH, COOH, CH.sub.2OCH.sub.2CH.sub.2OH,
CH.sub.2N(CH.sub.3).sub.2,
CH.sub.2--O--(CH.sub.2).sub.2N(CH.sub.3).sub.2,
COOCH.sub.2CH.sub.2N(CH.sub.3).sub.2, COO(CH.sub.2)COOH. It may
also be .dbd.O, in which case n is typically 1 or 2. In one
embodiment, when n equals 2, then R.sup.1 may be 2,6-dimethyl when
Z is counted as position 1. In other particular embodiments when n
equals 1, R.sup.1 may be methyl, CH.sub.2OH or
CH.sub.2OCH.sub.3.
[0046] R.sup.2 may be H, halo, CN, OR', SR', SOR', SO.sub.2R',
NR.sub.12, NR'(CO)R', or NR'SO.sub.2R', wherein each R.sup.1 is
independently H or an optionally substituted group selected from
alkyl (1-6C), heteroaryl (5-12C), and aryl (6-10C); or R.sup.2 may
be an optionally substituted group selected from alkyl (1-8C),
alkenyl (2-8C), or alkynyl (2-8C), heteroalkyl (2-8C),
heteroalkenyl (2-8C), heteroalkynyl (2-8C), aryl (6-10C),
heteroaryl (5-12C), O-aryl (6-10C), O-heteroaryl (5-12C) and
C6-C12-aryl-C1-C8-alkyl. In particular embodiments, R.sup.2 may be
H or 1-8C alkyl, a 1-6C alkyl or even more particularly a 1-4C
alkyl. In specific examples, R may be H, methyl, ethyl, isopropyl,
propyl, cyclopropyl, n-butyl or isobutyl. In a preferred
embodiment, R.sup.2 is H.
[0047] Each R.sup.3 may independently be H, alkyl, alkenyl or
alkynyl, for example. Where it makes sense chemically, each of
these groups (other than H) can be substituted. In more particular
embodiments, R.sup.3 is H or 1-8 C alkyl, more particularly 1-6 C
alkyl or 1-4 C alkyl. In even more particular embodiments R.sup.2
is H or methyl.
[0048] Each R.sup.4 can be H, OH, alkyl (1-4C), alkenyl (2-4C),
OR', C(O)R, C(O)OR', C(O)NR.sup.2, CN, or Ar.sup.1, wherein each R
is H or optionally substituted alkyl (1-4C). In certain
embodiments, R.sup.4 is H or OH; H is sometimes preferred.
[0049] X.sup.1 may or may not be present: it is absent when n is 0,
in which case the (Ar.sup.1).sub.2CR.sup.4 group is directly bonded
to N of the central piperidine/piperazine ring in formula (I).
However, to the extent that X.sup.1 is present, X.sup.1 is an
alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene
or heteroalkynylene as defined above and may be optionally
substituted also as defined above. When X.sup.1 is present,
particular embodiments of X.sup.1 include an optionally substituted
alkylene (1-4C), alkenylene (2-4C), alkynylene (2-4C),
heteroalkylene (2-4C), heteroalkenylene (2-4C), or heteroalkynylene
(2-4C). More particular embodiments of X.sup.1 include an
optionally substituted alkylene (1-4C) or a heteroalkylene (2-4C).
Even more particularly, X.sup.1 is CH.sub.2CO; NRCH.sub.2CO, where
R is H or alkyl (1-4C); OCH.sub.2CO; SCH.sub.2CO; SOCH.sub.2CO; or
SO.sub.2CH.sub.2CO.
[0050] X.sup.2 is an optionally substituted alkylene, alkenylene,
alkynylene, heteroalkylene, heteroalkenylene or heteroalkynylene as
defined above. In more particular embodiments, X.sup.2 is an
optionally substituted alkylene (1-4C), alkenylene (2-4C),
alkynylene (2-4C), heteroalkylene (2-4C), heteroalkenylene (2-4C),
or heteroalkynylene (2-4C), and even more particularly X.sup.2 is
an optionally substituted alkylene (1-4C) or an optionally
substituted alkylene (1-2C). In particular embodiments, X.sup.2 is
CH.sub.2 or CO.
[0051] Each Ar.sup.1 and Ar.sup.2 is independently an optionally
substituted aromatic or heteroaromatic ring as defined above. "Each
Ar.sup.1 and Ar.sup.2 can be substituted with 0-5 substituents,
preferably O-2 substituents.
[0052] In certain embodiments, each Ar.sup.1 is phenyl, so the
group (Ar.sup.1).sub.2CR.sup.4 represents a benzhydryl group.
Optionally, this benzhydryl group may be substituted at the methine
carbon or on one or both phenyl rings. In some embodiments, each
Ar.sup.1 is unsubstituted or at least one Ar.sup.1 is
unsubstituted. In other embodiments, each Art is substituted and
preferably both Ar.sup.1 rings have the same substituents in such
embodiments. Preferred substituents for Ar.sup.1 include halo,
especially F and Cl, and CF.sub.3, Me, CN, and OMe. The
substituents can be at any position on Ar.sup.1, and in some
embodiments at least one substituent occupies a position either
ortho or para to the position on Ar.sup.1 that is attached to the
methine carbon of (Ar.sup.1).sub.2CR.sup.4 in formula (I).
[0053] Ar in certain embodiments represents a phenyl group or a 5-6
membered heteroaromatic group containing 1-2 heteroatoms selected
from N, O and S as ring members. In preferred embodiments Ar.sup.2
is phenyl or pyridyl; in certain of these embodiments it is phenyl
and is optionally substituted with up to three substituents. In
certain embodiments, it is unsubstituted or is substituted with 1-3
groups selected from halo, especially F and Cl, and CF.sub.3, Me,
CN, and OMe. The substituents can be at any position on Ar.sup.2,
and in some embodiments at least one substituent occupies a
position ortho to the position on Ar.sup.2 that is attached to the
isoxazole ring in formula (I).
[0054] The central ring may be either a piperazine ring when Z is N
or a piperidine ring when Z is CHNR.sup.3 (where R.sup.3 is as
defined above). In a more particular embodiment, the central ring
is a piperazine ring.
[0055] In some preferred embodiments, two or more of the
particularly described groups are combined into one compound: it is
often suitable to combine one of the specified embodiments of one
feature as described above with a specified embodiment or
embodiments of one or more other features as described above. For
example, a specified embodiment includes compounds wherein
(Ar.sup.1).sub.2CR.sup.4 is benzhydryl, and another specified
embodiment has X.sup.1 is an alkylene (1-4C) or heteroalkylene
(1-4C). Thus one preferred embodiment combines both of these
features together, i.e., (Ar.sup.1).sub.2CR.sup.4 is benzhydryl in
combination with X.sup.1 being alkylene (1-4C) or
(Ar.sup.1).sub.2CR.sup.4 is benzhydryl in combination with X.sup.1
being heteroalkylene (1-4C).
[0056] Other specified embodiments have Z=N. Thus additional
preferred embodiments include Z=N in combination with any of the
preferred combinations set forth above.
[0057] In some specific embodiments, n is 0 and in others n is 1.
Thus additional preferred embodiments include n=0 in combination
with any of the preferred combinations set forth above; other
preferred combinations include n=1 in combination with any of the
preferred combinations set forth above.
[0058] The compounds of the invention may have ionizable groups so
as to be capable of preparation as salts. These salts may be acid
addition salts involving inorganic or organic acids or the salts
may, in the case of acidic forms of the compounds of the invention
be prepared from inorganic or organic bases. Frequently, the
compounds are prepared or used as pharmaceutically acceptable salts
prepared as addition products of pharmaceutically acceptable acids
or bases. Suitable pharmaceutically acceptable acids and bases are
well-known in the art, such as hydrochloric, sulphuric,
hydrobromic, acetic, lactic, citric, or tartaric acids for forming
acid addition salts, and potassium hydroxide, sodium hydroxide,
ammonium hydroxide, caffeine, various amines, and the like for
forming basic salts. Methods for preparation of the appropriate
salts are well-established in the art.
[0059] In some cases, the compounds of the invention contain one or
more chiral centers. The invention includes each of the isolated
stereoisomeric forms as well as mixtures of stereoisomers in
varying degrees of chiral purity, including racemic mixtures. It
also encompasses the various diastereomers and tautomers that can
be formed.
[0060] Compounds of formula (I) are also useful for the manufacture
of a medicament useful to treat conditions characterized by
undesired N-type and/or T-type calcium channel activities.
[0061] In addition, the compounds of the invention may be coupled
through conjugation to substances designed to alter the
pharmacokinetics, for targeting, or for other reasons. Thus, the
invention further includes conjugates of these compounds. For
example, polyethylene glycol is often coupled to substances to
enhance half-life; the compounds may be coupled to liposomes
covalently or noncovalently or to other particulate carriers. They
may also be coupled to targeting agents such as antibodies or
peptidomimetics, often through linker moieties. Thus, the invention
is also directed to the compounds of formula (I) when modified so
as to be included in a conjugate of this type.
MODES OF CARRYING OUT THE INVENTION
[0062] The compounds of formula (1) including compounds where the
provisos do not apply are useful in the methods of the invention
and exert their desirable effects through their ability to modulate
the activity of N-type and/or T-type calcium channels. The
compounds of formula (1) are particularly useful in modulating the
activity of N-type calcium channels. This makes them useful for
treatment of certain conditions. Conditions where modulation of
N-type calcium channels is desired include: chronic and acute pain;
mood disorders such as anxiety, depression, and addiction;
neurodegenerative disorders; gastrointestinal disorders such as
inflammatory bowel disease and irritable bowel syndrome;
genitourinary disorders such as urinary incontinence, interstitial
colitis and sexual dysfunction; neuroprotection such as cerebral
ischemia, stroke and traumatic brain injury; and metabolic
disorders such as diabetes and obesity. Conditions where modulation
of T-type calcium channels is desired include: cardiovascular
disease; epilepsy; diabetes; certain types of cancer such as
prostate cancer; chronic and acute pain; sleep disorders;
Parkinson's disease; psychosis such as schizophrenia; and male
birth control.
[0063] Acute pain as used herein includes but is not limited to
nociceptive pain and post-operative pain. Chronic pain includes but
is not limited by: peripheral neuropathic pain such as
post-herpetic neuralgia, diabetic neuropathic pain, neuropathic
cancer pain, failed back-surgery syndrome, trigeminal neuralgia,
and phantom limb pain; central neuropathic pain such as multiple
sclerosis related pain, Parkinson disease related pain, post-stroke
pain, post-traumatic spinal cord injury pain, and pain in dementia;
musculoskeletal pain such as osteoarthritic pain and fibromyalgia
syndrome; inflammatory pain such as rheumatoid arthritis and
endometriosis; headache such as migraine, cluster headache, tension
headache syndrome, facial pain, headache caused by other diseases;
visceral pain such as interstitial cystitis, irritable bowel
syndrome and chronic pelvic pain syndrome; and mixed pain such as
lower back pain, neck and shoulder pain, burning mouth syndrome and
complex regional pain syndrome.
[0064] Anxiety as used herein includes but is not limited to the
following conditions: generalized anxiety disorder, social anxiety
disorder, panic disorder, obsessive-compulsive disorder, and
post-traumatic stress syndrome. Addiction includes but is not
limited to dependence, withdrawal and/or relapse of cocaine,
opioid, alcohol and nicotine.
[0065] Neurodegenerative disorders as used herein include
Parkinson's disease, Alzheimer's disease, multiple sclerosis,
neuropathies, Huntington's disease and amyotrophic lateral
sclerosis (ALS).
[0066] Cardiovascular disease as used herein includes but is not
limited to hypertension, pulmonary hypertension, arrhythmia (such
as atrial fibrillation and ventricular fibrillation), congestive
heart failure, and angina pectoris.
[0067] Epilepsy as used herein includes but is not limited to
partial seizures such as temporal lobe epilepsy, absence seizures,
generalized seizures, and tonic/clonic seizures.
[0068] For greater certainty, in treating osteoarthritic pain,
joint mobility will also improve as the underlying chronic pain is
reduced. Thus, use of compounds of the present invention to treat
osteoarthritic pain inherently includes use of such compounds to
improve joint mobility in patients suffering from
osteoarthritis.
[0069] While the compounds described above generally have this
activity, availability of this class of calcium channel modulators
permits a nuanced selection of compounds for particular disorders.
The availability of this class of compounds provides not only a
genus of general utility in indications that are affected by
calcium channel activity, but also provides a large number of
compounds which can be mined and manipulated for specific
interaction with particular forms of calcium channels. Compounds
may be active against both N-type and T-type calcium channels and
that may be of particular benefit for certain disorders,
particularly those indications modulated by both N-type and T-type
calcium channels. However, for some indications, it may be
desirable to have a compound that selectively modulates N-type or
T-type calcium channels. The availability of recombinantly produced
calcium channels of the .alpha..sub.1A-.alpha..sub.1I and
.alpha..sub.1S types set forth above, facilitates this selection
process. Dubel, S. J., et al., Proc. Natl. Acad. Sci. USA (1992)
89:5058-5062; Fujita, Y., et al., Neuron (1993) 10:585-598; Mikami,
A., et al., Nature (1989) 340:230-233; Mori, Y., et al., Nature
(1991) 350:398-402; Snutch, T. P., et al., Neuron (1991) 7:45-57;
Soong, T. W., et al., Science (1993) 260:1133-1136; Tomlinson, W.
J., et al., Neuropharmacology (1993) 32:1117-1126; Williams, M. E.,
et al., Neuron (1992) 8:71-84; Williams, M. E., et al., Science
(1992) 257:389-395; Perez-Reyes, et al., Nature (1998) 391:896-900;
Cribbs, L. L., et al., Circulation Research (1998) 83:103-109; Lee,
J. H., et al., Journal of Neuroscience (1999) 19:1912-1921; McRory,
J. E., et al., Journal of Biological Chemistry (2001)
276:3999-4011.
[0070] It is known that calcium channel activity is involved in a
multiplicity of disorders, and particular types of channels are
associated with particular conditions. The association of N-type
and T-type channels in conditions associated with neural
transmission would indicate that compounds of the invention which
target N-type receptors are most useful in these conditions. Many
of the members of the genus of compounds of formula (I) exhibit
high affinity for N-type channels and/or T-type channels. Thus, as
described below, they are screened for their ability to interact
with N-type and/or T-type channels as an initial indication of
desirable function. It is particularly desirable that the compounds
exhibit IC.sub.50 values of <1 .mu.M. The IC.sub.50 is the
concentration which inhibits 50% of the calcium, barium or other
permeant divalent cation flux at a particular applied potential.
There are three distinguishable types of calcium channel
inhibition. The first, designated "open channel blockage," is
conveniently demonstrated when displayed calcium channels are
maintained at an artificially negative resting potential of about
-100 mV (as distinguished from the typical endogenous resting
maintained potential of about -70 mV). When the displayed channels
are abruptly depolarized under these conditions, calcium ions are
caused to flow through the channel and exhibit a peak current flow
which then decays. Open channel blocking inhibitors diminish the
current exhibited at the peak flow and can also accelerate the rate
of current decay.
[0071] This type of inhibition is distinguished from a second type
of block, referred to herein as "inactivation inhibition." When
maintained at less negative resting potentials, such as the
physiologically important potential of -70 mV, a certain percentage
of the channels may undergo conformational change, rendering them
incapable of being activated--i.e., opened--by the abrupt
depolarization. Thus, the peak current due to calcium ion flow will
be diminished not because the open channel is blocked, but because
some of the channels are unavailable for opening (inactivated).
"Inactivation" type inhibitors increase the percentage of receptors
that are in an inactivated state.
[0072] A third type of inhibition is designated "resting channel
block". Resting channel block is the inhibition of the channel that
occurs in the absence of membrane depolarization, that would
normally lead to opening or inactivation. For example, resting
channel blockers would diminish the peak current amplitude during
the very first depolarization after drug application without
additional inhibition during the depolarization.
[0073] In order to be maximally useful in treatment, it is also
helpful to assess the side reactions which might occur. Thus, in
addition to being able to modulate a particular calcium channel, it
is desirable that the compound has very low activity with respect
to the HERG K.sup.+ channel which is expressed in the heart.
Compounds that block this channel with high potency may cause
reactions which are fatal. Thus, for a compound that modulates the
calcium channel, it should also be shown that the HERG K.sup.+
channel is not inhibited. Similarly, it would be undesirable for
the compound to inhibit cytochrome p450 since this enzyme is
required for drug detoxification. Finally, the compound will be
evaluated for calcium ion channel type specificity by comparing its
activity among the various types of calcium channels, and
specificity for one particular channel type is preferred. The
compounds which progress through these tests successfully are then
examined in animal models as actual drug candidates.
[0074] The compounds of the invention modulate the activity of
calcium channels; in general, said modulation is the inhibition of
the ability of the channel to transport calcium. As described
below, the effect of a particular compound on calcium channel
activity can readily be ascertained in a routine assay whereby the
conditions are arranged so that the channel is activated, and the
effect of the compound on this activation (either positive or
negative) is assessed. Typical assays are described hereinbelow in
Examples 14-17.
[0075] Libraries and Screening
[0076] The compounds of the invention can be synthesized
individually using methods known in the art per se, or as members
of a combinatorial library.
[0077] Synthesis of combinatorial libraries is now commonplace in
the art. Suitable descriptions of such syntheses are found, for
example, in Wentworth, Jr., P., et al., Current Opinion in Biol.
(1993) 9:109-115; Salemme, F. R., et al, Structure (1997)
5:319-324. The libraries contain compounds with various
substituents and various degrees of unsaturation, as well as
different chain lengths. The libraries, which contain, as few as
10, but typically several hundred members to several thousand
members, may then be screened for compounds which are particularly
effective against a specific subtype of calcium channel, i.e., the
N-type channel. In addition, using standard screening protocols,
the libraries may be screened for compounds that block additional
channels or receptors such as sodium channels, potassium channels
and the like.
[0078] Methods of performing these screening functions are well
known in the art. These methods can also be used for individually
ascertaining the ability of a compound to agonize or antagonize the
channel. Typically, the channel to be targeted is expressed at the
surface of a recombinant host cell such as human embryonic kidney
cells. The ability of the members of the library to bind the
channel to be tested is measured, for example, by the ability of
the compound in the library to displace a labeled binding ligand
such as the ligand normally associated with the channel or an
antibody to the channel. More typically, ability to antagonize the
channel is measured in the presence of calcium, barium or other
permeant divalent cation and the ability of the compound to
interfere with the signal generated is measured using standard
techniques. In more detail, one method involves the binding of
radiolabeled agents that interact with the calcium channel and
subsequent analysis of equilibrium binding measurements including,
but not limited to, on rates, off rates, K.sub.d values and
competitive binding by other molecules.
[0079] Another method involves the screening for the effects of
compounds by electrophysiological assay whereby individual cells
are impaled with a microelectrode and currents through the calcium
channel are recorded before and after application of the compound
of interest.
[0080] Another method, high-throughput spectrophotometric assay,
utilizes loading of the cell lines with a fluorescent dye sensitive
to intracellular calcium concentration and subsequent examination
of the effects of compounds on the ability of depolarization by
potassium chloride or other means to alter intracellular calcium
levels.
[0081] As described above, a more definitive assay can be used to
distinguish inhibitors of calcium flow which operate as open
channel blockers, as opposed to those that operate by promoting
inactivation of the channel or as resting channel blockers. The
methods to distinguish these types of inhibition are more
particularly described in the examples below. In general,
open-channel blockers are assessed by measuring the level of peak
current when depolarization is imposed on a background resting
potential of about -100 mV in the presence and absence of the
candidate compound. Successful open-channel blockers will reduce
the peak current observed and may accelerate the decay of this
current. Compounds that are inactivated channel blockers are
generally determined by their ability to shift the voltage
dependence of inactivation towards more negative potentials. This
is also reflected in their ability to reduce peak currents at more
depolarized holding potentials (e.g., -70 mV) and at higher
frequencies of stimulation, e.g., 0.2 Hz vs. 0.03 Hz. Finally,
resting channel blockers would diminish the peak current amplitude
during the very first depolarization after drug application without
additional inhibition during the depolarization.
[0082] Utility and Administration
[0083] For use as treatment of human and animal subjects, the
compounds of the invention can be formulated as pharmaceutical or
veterinary compositions. Depending on the subject to be treated,
the mode of administration, and the type of treatment
desired--e.g., prevention, prophylaxis, therapy; the compounds are
formulated in ways consonant with these parameters. A summary of
such techniques is found in Remington's Pharmaceutical Sciences,
latest edition, Mack Publishing Co., Easton, Pa., incorporated
herein by reference.
[0084] In general, for use in treatment, the compounds of formula
(1) may be used alone, as mixtures of two or more compounds of
formula (1) or in combination with other pharmaceuticals. An
example of other potential pharmaceuticals to combine with the
compounds of formula (1) would include pharmaceuticals for the
treatment of the same indication but having a different mechanism
of action from N-type or T-type calcium channel blocking. For
example, in the treatment of pain, a compound of formula (1) may be
combined with another pain relief treatment such as an NSAID, or a
compound which selectively inhibits COX-2, or an opioid, or an
adjuvant analgesic such as an antidepressant. Another example of a
potential pharmaceutical to combine with the compounds of formula
(1) would include pharmaceuticals for the treatment of different
yet associated or related symptoms or indications. Depending on the
mode of administration, the compounds will be formulated into
suitable compositions to permit facile delivery.
[0085] Formulations may be prepared in a manner suitable for
systemic administration or topical or local administration.
Systemic formulations include those designed for injection (e.g.,
intramuscular, intravenous or subcutaneous injection) or may be
prepared for transdermal, transmucosal, or oral administration. The
formulation will generally include a diluent as well as, in some
cases, adjuvants, buffers, preservatives and the like. The
compounds can be administered also in liposomal compositions or as
microemulsions.
[0086] For injection, formulations can be prepared in conventional
forms as liquid solutions or suspensions or as solid forms suitable
for solution or suspension in liquid prior to injection or as
emulsions. Suitable excipients include, for example, water, saline,
dextrose, glycerol and the like. Such compositions may also contain
amounts of nontoxic auxiliary substances such as wetting or
emulsifying agents, pH buffering agents and the like, such as, for
example, sodium acetate, sorbitan monolaurate, and so forth.
[0087] Various sustained release systems for drugs have also been
devised. See, for example, U.S. Pat. No. 5,624,677.
[0088] Systemic administration may also include relatively
noninvasive methods such as the use of suppositories, transdermal
patches, transmucosal delivery and intranasal administration. Oral
administration is also suitable for compounds of the invention.
Suitable forms include syrups, capsules, tablets, as is understood
in the art.
[0089] For administration to animal or human subjects, the dosage
of the compounds of the invention is typically 0.1-15 mg/kg,
preferably 0.1-1 mg/kg. However, dosage levels are highly dependent
on the nature of the condition, drug efficacy, the condition of the
patient, the judgment of the practitioner, and the frequency and
mode of administration.
[0090] Synthesis of the Invention Compounds
[0091] The compounds of the invention may be synthesized using
conventional methods. Reaction Scheme 1 is illustrative and may be
used to prepare compounds with a carbonyl group between the
piperazine ring and the isoxazole moiety (7) or without such a
carbonyl group (6).
##STR00003##
[0092] The piperidine analog can be substituted and reaction of the
nitrogen of CHNH.sub.2 substitutes for the nitrogen of piperazine.
Reaction Scheme 1 utilizes a generic Y-piperazine to be coupled to
the isoxazole containing compounds (4 or 5) to yield the final
products (6 and 7). In some cases, the desired piperazine
containing compound may be commercially available such as the
unsubstituted 1-benzhydryl-piperazine. In other cases, the desired
piperazine containing compound may also be synthesized using
conventional methods. Reaction Schemes 2 and 3 are illustrative of
synthetic methods that could be used for two particular series of
compounds.
##STR00004##
##STR00005##
[0093] For greater certainty, R in Reaction Scheme 1 and R and R'
in Reaction Scheme 2 are not limited to the monosubstituted
compounds. For particular embodiments as provided in Table 1, R in
Reaction Scheme 2 is 2,4-dimethyl or 2,4-dichloro.
[0094] An alternate synthetic methodology is illustrated in
Reaction Scheme 4 starting with 4 from Reaction Scheme 1 as
follows:
##STR00006##
[0095] In specific embodiments of the present invention as
exemplified below, X is CH.sub.2, NH, O, S, S.dbd.O and SO.sub.2.
By replacing the BOC-protected piperazine in the preceding reaction
schemes with a similarly protected 4-(aminomethyl)piperidine,
compounds of formula (1) wherein Z is CHNR.sup.3 can be prepared
similarly.
[0096] The following examples are intended to illustrate the
synthesis of a representative number of compounds. Accordingly, the
following examples are intended to illustrate but not to limit the
invention. Additional compounds not specifically exemplified may be
synthesized using conventional methods in combination with the
methods described hereinbelow.
EXAMPLE 1
Synthesis of 3-(2-fluorophenyl)isoxazole-5-carbaldehyde
##STR00007##
[0097] A. Synthesis of 2-fluorobenzaldehyde oxime
##STR00008##
[0099] 2-fluorobenzaldehyde (10 g, 80.6 mmol) and hydroxylamine
hydrochloride (11.2 g, 161 mmol) were stirred in EtOH:H.sub.2O
(95:5, 150 mL). NaOH (6.4 g, 191 mmol) was added and the reaction
refluxed for 16 h. The reaction was reduced in volume to one
quarter and partitioned between EtOAc and H.sub.2O. The organic
layer was dried over MgSO.sub.4 and concentrated to yield crude
product that was sufficiently pure to use in subsequent
reactions.
B. Synthesis of (3-(2-fluorophenyl)isoxazol-5-yl)methanol
##STR00009##
[0101] 2-fluorobenzaldehyde oxime (10.2 g, 73.4 mmol) and pyridine
(506 mL, 7 mmol) were stirred under N.sub.2 in dry THF at
60.degree. C. N-chlorosuccinimide (10.6 g, 80 mmol) was added and
stirring continued for 45 min. TEA (12.2 mL, 88 mmol) and propargyl
alcohol were added and stirring continued for a further 16 h. The
reaction was concentrated and the residue taken up in DCM. The
organic layer was washed sequentially with 1M HCl and H.sub.2O,
dried over MgSO.sub.4 and concentrated. The crude product was
purified by column chromatography (100% DCM to 20% EtOAc/DCM) to
give product (8.5 g, 60%) as a clear colorless oil that slowly
solidifies at room temperature.
C. Synthesis of 3-(2-fluorophenyl)isoxazole-5-carbaldehyde
##STR00010##
[0103] (3-(2-fluorophenyl)isoxazol-5-yl)methanol (1.45 g, 7.7 mmol)
and pyridinium chlorochromate (3.2 g, 15 mmol) were stirred in DCM
(40 mL) at rt for 2 h. Additional pyridinium chlorochromate (2.0 g,
9.3 mmol) was added and stirring continued for a further 2 h. The
reaction was filtered through a bed of silica. The solid residue
was triturated with Et.sub.2O and also filtered. The filtrates were
combined, concentrated and purified by column chromatography (2.5%
MeOH/DCM) to give the desired product (1.05 g, 73%) as a clear
colorless oil.
EXAMPLE 2
Synthesis of 3(2-fluorophenyl)isoxazole-5-carboxylic acid
##STR00011##
[0104] Method A:
[0105] (3-(2-fluorophenyl)isoxazol-5-yl)methanol (synthesized
according to Example 1B) (1.5 g, 7.8 mmol) was stirred in a
solution of Na.sub.2CO.sub.3 (170 mg, 1.6 mmol) in H.sub.2O (50
mL). KMnO.sub.4 (2.45 g, 15.5 mmol) was added and the reaction
stirred at rt for 2 h. Additional KMnO.sub.4 (1.0 g, 6.3 mmol) was
added and stirring continued for a further 16 h. The reaction was
filtered, the filtrate acidified with dilute H.sub.2SO.sub.4 and
extracted twice with Et.sub.2O. The organic layer was washed with
1M NaOH. The basic layer was washed twice with Et.sub.2O, acidified
with 1M HCl and extracted with Et.sub.2O. The final organic
extracts were combined, dried over MgSO.sub.4 and concentrated to
give the desired product as a white solid (0.8 g, 51%).
Method B:
[0106] (3-(2-fluorophenyl)isoxazol-5-yl)methanol (synthesized
according to Example 1B) (1 g, 5.2 mmol) was stirred in acetone (40
mL) at -5.degree. C. KMnO.sub.4 (0.87 g, 5.5 mmol) was added in
portions over two hours whilst maintaining the temperature below
0.degree. C. After addition, the reaction was stirred for a further
4 hours at -5.degree. C.-0.degree. C. 1M HCl (50 mL) and Et.sub.2O
(50 mL) were added and the reaction stirred for 30 mins. The
reaction was filtered through cellite, the organic layer separated
and the aqueous layer extracted with additional Et.sub.2O. The
organic layers were combined, dried (MgSO.sub.4) and concentrated
to give the desired product as a white solid (0.69 g, 60%).
EXAMPLE 3
Synthesis of 1-((2,4-dimethylphenyl)(phenyl)methyl)piperazine
##STR00012##
[0107] A. Synthesis of (2,4-dimethylphenyl)(phenyl)methanol
##STR00013##
[0109] Phenyl magnesium bromide (3.0 mol solution in Et.sub.2O)
(9.3 mL, 27.9 mmol) was stirred in dry Et.sub.2O (60 mL) at
0.degree. C. under a N.sub.2 atmosphere. 2,4-Dimethylbenzaldeyhde
was dissolved in Et.sub.2O (10 mL) and added dropwise to the
reaction over 15 minutes. The reaction was then refluxed for 1.5 h.
After cooling, the reaction was quenched with 1M HCl (40 mL). The
organics were separated, dried over MgSO.sub.4 and concentrated.
The crude product was purified by column chromatography (15:1 Pet
ether:EtOAc) to give the desired product (2.84 g, 48%).
B. Synthesis of 1-(chloro(phenyl)methyl)-2,4-dimethylbenzene
##STR00014##
[0111] (2,4-dimethylphenyl)(phenyl)methanol (7.2 g, 34 mmol) was
stirred in dry DCM (50 mL) at room temperature under a N.sub.2
atmosphere. Thionyl chloride (10 mL, 136 mmol) was added and the
reaction heated at reflux for 3.5 h. The reaction was concentrated
and dried under high vacuum for 16 h to yield crude product that
was sufficiently pure to use in subsequent reactions.
C. Synthesis of
1-((2,4-dimethylphenyl)(phenyl)(methyl)piperazine
##STR00015##
[0113] 1-(chloro(phenyl)methyl)-2,4-dimethylbenzene (34 mmol),
K.sub.2CO.sub.3 (4.7 g, 34 mmol), KI (5.6 g, 34 mmol) and
piperazine (11.7 g, 136 mmol) were heated at reflux in 2-butanone
(100 mL) for 16 h. After cooling, the reaction was diluted with DCM
(100 mL) and washed with H.sub.2O (2.times.75 mL). The organic
layer was separated, dried over MgSO.sub.4 and concentrated. The
crude product was purified by column chromatography (100% DCM, to
16% MeOH/DCM) to give the desired product (3.24 g, 54%) as a brown
oil that slowly solidifies.
EXAMPLE 4
Synthesis of 3,3-diphenyl-1-(piperazin-1-yl)propan-1-one
##STR00016##
[0114] A. Synthesis of
tert-butyl-4-(3,3-diphenylpropanoyl)piperazine-1-carboxylate
##STR00017##
[0116] 3,3'-Diphenylpropionic acid (3.35 g, 14.8 mmol), tert-butyl
piperazine-1-carboxylate (2.5 g, 13.4 mmol), EDC.HCl (5.3 g, 26.8
mmol) and DMAP (cat) were stirred in dry DCM (50 mL) at rt under a
N.sub.2 atmosphere for 48 h. The reaction was diluted with DCM (50
mL) and washed sequentially with H.sub.2O (50 mL) and saturated
brine (50 mL). The organic layer was separated, dried over
MgSO.sub.4 and concentrated. The crude product was purified by
column chromatography (2.5% MeOH/DCM) to give the desired product
(3.45 g, 70%) as a white solid.
B. Synthesis of 3,3-diphenyl-1-(piperazin-1-yl)propan-1-one
##STR00018##
[0118] tert-butyl 4-(3,3-diphenylpropanoyl)piperazine-1-carboxylate
(11) (3.45 g, 9.4 mmol) was stirred at rt in DCM (100 mL). TFA (25
mL) was added and the reaction stirred for 1 h. The reaction was
concentrated in-vacuo, the residue taken up in DCM (100 mL) and
washed with 1M NaOH (2.times.50 mL). The organic layer was
separated, washed with H.sub.2O (50 mL), dried over MgSO.sub.4 and
concentrated to give the desired product (2.54 g, 92%) that was
sufficiently pure to use in subsequent reactions.
EXAMPLE 5
Synthesis of 2-(benzhydrylamino)acetic acid
##STR00019##
[0120] To a solution of aminodiphenylmethane 1.85 g (10 mmol) in
DMF (20 ml) was added ethyl bromoacetate 1.2 ml (11 mmol) and
potassium carbonate 1.38 g (10 mmol). The reaction mixture was
heated at 60.degree. C. for two days before being concentrated.
Water was then added and the reaction product was extracted with
ethyl acetate (2.times.50 ml). The organic solution was dried over
sodium sulfate and concentrated to give 3 g of crude ester. To the
ester, lithium hydroxide 1.25 g (30 mmol) and methanol (10 ml), THF
(30 ml) and water (10 ml) was then added. The mixture was
subsequently stirred at room temperature overnight before being
concentrated to remove solvent. The reaction mixture was then
neutralized with 2N HCl to pH.about.3, and the reaction product was
extracted with ethyl acetate (40 ml). The organic layer was then
dried over sodium sulfate and concentrated to give the desired
product (2.0 g).
EXAMPLE 6
Synthesis of 2-(benzhydryloxy)acetic acid
##STR00020##
[0122] To a solution of benzhydrol 3.68 g (20 mmol) in THF (40 ml)
was added sodium hydride (1 g, 24 mmol). The reaction mixture was
then stirred at room temperature for half an hour. 2.4 ml ethyl
bromoacetate (22 mmol) was added, and the reaction mixture was
stirred at room temperature overnight. The reaction was then
quenched with methanol and concentrated. Water was then added and
the reaction product was extracted with ethyl acetate (100 ml). The
organic solution was dried over sodium sulfate and concentrated to
give 5.6 g of crude ester. To the ester, lithium hydroxide 2.5 g
(60 mmol) and methanol (15 ml), THF (45 ml) and water (15 ml) were
added. The mixture was stirred at room temperature overnight, and
then concentrated to remove solvent. The reaction mixture was
neutralized with 2N HCl to pH-3, and the reaction product was
extracted with ethyl acetate (40 ml). The organic layer was dried
over sodium sulfate and concentrated to give 4.2 g of the desired
product.
EXAMPLE 7
Synthesis of 2-(benzhydrythio)acetic acid
##STR00021##
[0124] 10 g of thiourea was dissolved in 57 ml of 48% HBr and 10 ml
of water. The reaction mixture was heated to 60.degree. C., and
20.2 g of benzhydrol was added. The temperature was increased to
90.degree. C. and then cooled to room temperature. Crystals were
filtered off and washed with water. The above crystals were then
added to 30% sodium hydroxide (35 ml). The mixture was heated to
70.degree. C., and then chloroacetic acid (11.44 g in 22 ml of
water) was added slowly. The mixture was refluxed for half an hour
after the addition. The reaction mixture was then cooled to room
temperature to give desired product (25 g).
EXAMPLE 8
Synthesis of 2-(benzhydrylsulfinyl)acetic acid
##STR00022##
[0126] 10 g of thiourea was dissolved in 57 ml of 48% HBr and 10 ml
of water. The reaction mixture was heated to 60.degree. C., and
benzhydrol (20.2 g) was added. The temperature was increased to
90.degree. C., and then cooled to room temperature. The crystals
were filtered off and washed with water. The above crystals were
then added to 30% sodium hydroxide (35 ml). The mixture was heated
to 70.degree. C., and chloroacetic acid (11.44 g in 22 ml of water)
was added slowly. The mixture was refluxed for half an hour after
the addition. 14.3 ml hydrogen peroxide (30%) was added to the
above solution over 3 hours at room temperature. Water (22 ml) was
added and the reaction mixture was filtered. The filtrate was
acidified with concentrated HCl (d=1.18). The resulting solid was
filtered off and dried to give the desired product (13 g).
EXAMPLE 9
Synthesis of (3-(2-fluorophenyl)isoxazol-5-yl)methyl piperazine
##STR00023##
[0128] 3-(2-fluorophenyl)isoxazole-5-carbaldehyde (synthesized
according to Example 1) (1.4 g, 7.31 mmol) and Boc-piperazine (1.63
g, 8.7 mmol) were stirred at rt in dry DCM (30 mL). Sodium
triacetoxyborohydride (2.3 g, 11 mmol) and AcOH (1.0 mL,) were
added and the reaction stirred for 24 h. The reaction was then
diluted with DCM (70 mL) and washed with a saturated solution of
NaHCO.sub.3 (40 mL). The organic layer was separated, dried over
MgSO.sub.4 and concentrated. The crude product was purified by
column chromatography (10%/o MeOH/DCM) to give the product as a
colourless oil. The product was then dissolved in DCM and
trifluoroacetic acid (15 ml) was added and resulting mixture
stirred at room temperature for 2 hours. The reaction mixture was
concentrated, dissolved in methylene chloride and washed with
saturated sodium bicarbonate and brine. The methylene chloride
solution was dried over sodium sulfate and concentrated to give the
desired product.
EXAMPLE 10
Synthesis of
(4-benzhydrylpiperazin-1-yl)(3-phenylisoxazol-5-yl)methanone
(Compound No. 1)
##STR00024##
[0130] 3-phenylisoxazole-5-carboxylic acid (synthesized under the
general methodology of Example 2) (176 mg, 0.93 mmol) was stirred
with 1,1'-carbonyldiimidazole (165 mg, 1.02 mmol) in dry THF at rt
under a N.sub.2 atmosphere for 30 mins. 1-diphenylmethylpiperazine
(211 mg, 0.84 mmol) was added and the reaction stirred for 2 h.
Reaction monitored by TLC and upon completion the solvent was
removed in-vacuo. The crude product was purified by column
chromatography (2.5% MeOH/DCM) to give the product as a colourless
oil. The product was dissolved in DCM and stirred with
HCl/Et.sub.2O for 45 mins at rt. The solvent was removed in-vacuo
and the resultant white solid triturated with Et.sub.2O to give the
HCl salt of the desired product (42 mg, 10%) as a white solid.
EXAMPLE 11
Synthesis of
5-((4-benzhydrylpiperazin-1-yl)methyl)-3-phenylisoxazole (Compound
No. 2)
##STR00025##
[0132] 3-phenylisoxazole-5-carbaldehyde (synthesized under the
general methodology of Example 1) (130 mg, 0.75 mmol) and
1-diphenylmethylpiperazine (210 mg, 0.83 mmol) were stirred at rt
in dry DCM (5 mL). Sodium triacetoxyborohydride (318 mg, 1.5 mmol)
and AcOH (86 mL, 1.5 mmol) were added and the reaction stirred for
24 h. The reaction was diluted with DCM (15 mL) and washed with
NaHCO.sub.3 saturated solution (5 mL). The organic layer was
separated, dried over MgSO.sub.4 and concentrated. The crude
product was purified by column chromatography (2.5% MeOH/DCM) to
give the product as a colourless oil. The product was dissolved in
DCM and stirred with HCl/Et.sub.2O for 45 mins at rt. The solvent
was removed in-vacuo and the resultant white solid triturated with
Et.sub.2O to give the HCl salt of the desired product (237 mg, 53%)
as a white solid.
EXAMPLE 12
Synthesis of
2-(benzhydrylamino)-1-(4-((3-(2-fluorophenyl)isoxazol-5-yl)methyl)piperaz-
in-1-yl)ethanone (Compound No. 17)
##STR00026##
[0134] To a solution of 3-(2-fluorophenyl)isoxazole-5-yl)methyl
piperazine (synthesized according to Example 9) (0.16 g, 0.6 mmol)
dissolved in methylene chloride (5 ml) was added
2-(benzhydrylamino)acetic acid, 0.16 g (0.6 mmol), EDC 0.2 g (1.2
mmole) and trace of DMPA, and the reaction mixture was stirred at
room temperature overnight. The reaction mixture was then
concentrated and dissolved in ethyl acetate (10 ml). The reaction
mixture was subsequently washed with saturated sodium bicarbonate
solution and brine before being dried over sodium sulfate and
concentrated. The resulting residue was applied to flash column
chromatography using ether and then with ethyl acetate as eluents
to give the desired product (00.10 g).
EXAMPLE 13
[0135] Following the procedures set forth above, the following
compounds listed in Table 1 below were prepared. Mass spectrometry
was employed with the final compound and at various stages
throughout the synthesis as a confirmation of the identity of the
product obtained (M+1). For the mass spectrometric analysis,
samples were prepared at an approximate concentration of 1 .mu.g/mL
in acetonitrile with 0.1% formic acid. Samples were then manually
infused into an Applied Biosystems API3000 triple quadrupole mass
spectrometer and scanned in Q1 in the range of 50 to 700 m/z.
TABLE-US-00002 TABLE 1 Cmpd Mass Spec No. Name Structure (m/z) 1
(4-benzhydrylpiperazin-1-yl)(3- phenylisoxazol-5-yl)methanone
##STR00027## 424.5 2 5-((4-benzhydrylpiperazin-1-yl)methyl)-
3-phenylisoxazole ##STR00028## 410.4 3
(4-benzhydrylpiperazin-1-yl)(3-(2-
fluorophenyl)isoxazol-5-yl)methanone ##STR00029## 442.3 4
(4-benzhydrylpiperazin-1-yl)(3-(2-
methoxyphenyl)isoxazol-5-yl)methanone ##STR00030## 454.3 5
5-((4-benzhydry1piperazin-1-yl)methyl)-
3-(2-methoxyphenyl)isoxazole ##STR00031## 440.4 6
5-((4-benzhydry1piperazin-1-yl)methyl)- 3-(2-fluorophenyl)isoxazole
##STR00032## 428.2 7 1-(4-((3-(2-fluorophenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)-3,3- diphenylpropan-1-one ##STR00033##
470.5 8 1-(4-((3-(2-methoxyphenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)-3,3- diphenylpropan-1-one ##STR00034##
482.4 9 3,3-diphenyl-1-(4-((3-phenylisoxazol-5-
yl)methyl)piperazin-1-yl)propan-1-one ##STR00035## 452.4 10
5-((4-((2,4- dimethylphenyl)(phenyl)methyl)piperazin-
1-yl)methyl)-3-phenylisoxazole ##STR00036## 438.5 11 (4-((2,4-
dimethylphenyl)(phenyl)methyl)piperazin-
1-yl)(3-(2-fluorophenyl)isoxazol-5- yl)methanone ##STR00037## 470.5
12 5-((4-((2,4- dimethylphenyl)(phenyl)methyl)piperazin-
1-yl)methyl)-3-(2- fluorophenyl)isoxazole ##STR00038## 456.4 13
5-((4-((2,4- dimethylphenyl)(phenyl)methyl)piperazin-
1-yl)methyl)-3-(2- methoxyphenyl)isoxazole ##STR00039## 468.5 14
5-((4-((2,4- dichlorophenyl)(phenyl)methyl)piperazin-
1-yl)methyl)-3-phenylisoxazole ##STR00040## 478.3 15 (4-((2,4-
dichlorophenyl)(phenyl)methyl)piperazin-
1-yl)(3-(2-fluorophenyl)isoxazol-5- yl)methanone ##STR00041## 510.2
16 5-((4-((2,4- dichlorophenyl)(phenyl)methyl)piperazin-
1-yl)methyl)-3-(2-fluorophenyl) isoxazole ##STR00042## 496.4 17
2-(benzhydrylamino)-1-(4-((3-(2- fluorophenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00043## 485.2 18
2-(benzhydryloxy)-1-(4-((3-(2- fluorophenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00044## 486.2 19
2-(benzhydrylthio)-1-(4-((3-(2- fluorophenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00045## 502.3 20
2-(benzhydrylsulfinyl)-1-(4-((3-(2- fluorophenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00046## 518.3 21
2-(benzhydrylamino)-1-(4-((3-(2- methoxyphenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00047## 497.4 22
2-(benzhydryloxy)-1-(4-((3-(2- methoxyphenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00048## 498.3 23
2-(benzhydrylthio)-1-(4-((3-(2- methoxyphenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00049## 514.3 24
2-(benzhydrylsulfinyl)-1-(4-((3-(2- methoxyphenyl)isoxazol-5-
yl)methyl)piperazin-1-yl)ethanone ##STR00050## 530.3 25
2-(benzhydrylamino)-1-(4-((3-
phenylisoxazol-5-yl)methyl)piperazin-1- yl)ethanone ##STR00051##
467.4 26 2-(benzhydryloxy)-1-(4-((3-
phenylisoxazol-5-yl)methyl)piperazin-1- yl)ethanone ##STR00052##
468.4 27 2-(benzhydrylthio)-1-(4-((3-
phenylisoxazol-5-yl)methyl)piperazin-1- yl)ethanone ##STR00053##
484.2 28 2-(benzhydrylsulfinyl)-1-(4-((3-
phenylisoxazol-5-yl)methyl)piperazin-1- yl)ethanone ##STR00054##
500.3 29 2-(benzhydrylamino)-1-(4-(3-(2- methoxyphenyl)isoxazole-5-
carbonyl)piperazin-1-yl)ethanone ##STR00055## 511.3
EXAMPLE 14
N-type Channel Blocking Activities of Various Invention
Compounds
[0136] A. Transformation of HEK cells:
[0137] N-type calcium channel blocking activity was assayed in
human embryonic kidney cells, HEK 293, stably transfected with the
rat brain N-type calcium channel subunits
(.alpha..sub.1B+.alpha..sub.2.delta.+.beta..sub.1b cDNA subunits).
Alternatively, N-type calcium channels
(.alpha..sub.1B+.alpha..sub.2.delta.+.beta..sub.1b cDNA subunits),
L-type channels (.alpha..sub.1C+.alpha..sub.2.delta.+.beta..sub.1b
cDNA subunits) and P/Q-type channels
(.alpha..sub.1A+.alpha..sub.2.delta.+.beta..sub.1b cDNA subunits)
were transiently expressed in HEK 293 cells. Briefly, cells were
cultured in Dulbecco's modified eagle medium (DMEM) supplemented
with 10% fetal bovine serum, 200 U/ml penicillin and 0.2 mg/ml
streptomycin at 37.degree. C. with 5% CO.sub.2. At 85% confluency
cells were split with 0.25% trypsin/1 mM EDTA and plated at 10%
confluency on glass coverslips. At 12 hours the medium was replaced
and the cells transiently transfected using a standard calcium
phosphate protocol and the appropriate calcium channel cDNA's.
Fresh DMEM was supplied and the cells transferred to 28.degree.
C./5% CO.sub.2. Cells were incubated for 1 to 2 days prior to whole
cell recording.
[0138] B. Measurement of Inhibition
[0139] Whole cell patch clamp experiments were performed using an
Axopatch 200B amplifier (Axon Instruments, Burlingame, Calif.)
linked to a personal computer equipped with pCLAMP software. The
external and internal recording solutions contained, respectively,
5 mM BaCl.sub.2, 10 mM MgCl.sub.2, 10 mM HEPES, 40 mM TEACl, 10 mM
glucose, 87.5 mM CsCl (pH 7.2) and 108 mM CsMS, 4 mM MgCl.sub.2, 9
mM EGTA, 9 mM HEPES (pH 7.2). Currents were typically elicited from
a holding potential of -80 mV to +10 mV using Clampex software
(Axon Instruments). Typically, currents were first elicited with
low frequency stimulation (0.067 Hz) and allowed to stabilize prior
to application of the compounds. The compounds were then applied
during the low frequency pulse trains for two to three minutes to
assess tonic block, and subsequently the pulse frequency was
increased to 0.2 Hz to assess frequency dependent block. Data were
analyzed using Clampfit (Axon Instruments) and SigmaPlot 4.0
(Jandel Scientific).
[0140] Specific data obtained for N-type channels are shown in
Table 2 below.
TABLE-US-00003 TABLE 2 N-type Calcium Channel Block Compound
IC.sub.50 @ 0.067 Hz (.mu.M) IC.sub.50 @ 0.2 Hz (.mu.M) 1 0.65 0.29
2 1.70 0.67 3 0.80 0.37 4 2.99 1.49 5 0.68 0.34 6 3.40 1.10 7 0.52
0.33 8 0.60 0.29 9 2.80 1.20 10 1.07 0.40 11 2.18 1.13 12 0.95 0.57
14 22.20 2.24 15 6.47 3.38 16 3.15 1.96
EXAMPLE 15
T-Type Channel Blocking Activities of Various Invention
Compounds
[0141] Standard patch-clamp techniques were employed to identify
blockers of T-type currents. Briefly, previously described HEK cell
lines stably expressing human .alpha..sub.1G T-type channels were
used for all the recordings (passage #: 4-20, 37.degree. C., 5%
CO.sub.2). To obtain T-type currents, plastic dishes containing
semi-confluent cells were positioned on the stage of a ZEISS
AXIOVERT S100 microscope after replacing the culture medium with
external solution (see below). Whole-cell patches were obtained
using pipettes (borosilicate glass with filament, O.D.: 1.5 mm,
I.D.: 0.86 mm, 10 cm length), fabricated on a SUTTER P-97 puller
with resistance values of .about.5 M.cndot. (see below for internal
solution).
TABLE-US-00004 TABLE 3 External Solution 500 ml - pH 7.4, 265.5
mOsm Salt Final mM Stock M Final ml CsCl 132 1 66 CaCl.sub.2 2 1 1
MgCl.sub.2 1 1 0.5 HEPES 10 0.5 10 glucose 10 -- 0.9 grams
TABLE-US-00005 TABLE 4 Internal Solution 50 ml - pH 7.3 with CsOH,
270 mOsm Salt Final mM Stock M Final ml Cs-Methanesulfonate 108 --
1.231 gr/50 ml MgCl2 2 1 0.1 HEPES 10 0.5 1 EGTA-Cs 11 0.25 2.2 ATP
2 0.2 0.025 (1 aliquot/2.5 ml) T-type currents were reliably
obtained by using two voltage protocols: (1) "non-inactivating",
and (2) "inactivation"
[0142] In the non-inactivating protocol, the holding potential is
set at -110 mV and with a pre-pulse at -100 mV for 1 second prior
to the test pulse at -40 mV for 50 ms. In the inactivation
protocol, the pre-pulse is at approximately -85 mV for 1 second,
which inactivates about 15% of the T-type channels.
##STR00056##
[0143] Test compounds were dissolved in external solution,
0.1-0.01% DMSO. After .about.10 min rest, they were applied by
gravity close to the cell using a WPI microfil tubing. The
"non-inactivated" pre-pulse was used to examine the resting block
of a compound. The "inactivated" protocol was employed to study
voltage-dependent block. However, the initial data shown below were
mainly obtained using the non-inactivated protocol only. IC.sub.50
values are shown for various compounds of the invention in Table
5.
TABLE-US-00006 TABLE 5 T-type Calcium Channel Block Compound
IC.sub.50 @ -100 mV (.mu.M) IC.sub.50 @ -80 mV (.mu.M) 1 >10.00
1.90 2 1.60 0.35 9 >10.00 1.70 10 9.21 2.18 11 14.79 2.77 12
3.69 0.83 14 >16.50 5.53
[0144] The results from Table 5 can be used in isolation to
indicate compounds that act as efficient T-type calcium channel
blockers. Alternatively, the results from Table 5 can be used in
conjunction with the results from Table 2 to indicate compounds
that are effective in blocking both N-type and T-type calcium
channels or are selective for N-type calcium channels.
EXAMPLE 16
[0145] Activity of Invention Compounds in Formalin-Induced Pain
Model
[0146] The effects of intrathecally delivered compounds of the
invention on the rat formalin model can also be measured. The
compounds can be reconstituted to stock solutions of approximately
10 mg/ml in propylene glycol. Typically eight Holtzman male rats of
275-375 g size are randomly selected per test article.
[0147] The following study groups are used, with test article,
vehicle control (propylene glycol) and saline delivered
intraperitoneally (IP):
TABLE-US-00007 TABLE 6 Formalin Model Dose Groups Test/Control
Article Dose Route Rats per group Compound 30 mg/kg IP 6 Propylene
glycol N/A IP 4 Saline N/A IP 7 N/A = Not Applicable
[0148] Prior to initiation of drug delivery baseline behavioral and
testing data can be taken. At selected times after infusion of the
Test or Control Article these data can then be again collected.
[0149] On the morning of testing, a small metal band (0.5 g) is
loosely placed around the right hind paw. The rat is placed in a
cylindrical Plexiglas chamber for adaptation a minimum of 30
minutes. Test Article or Vehicle Control Article is administered 10
minutes prior to formalin injection (50 .mu.l of 5% formalin) into
the dorsal surface of the right hindpaw of the rat. The animal is
then placed into the chamber of the automated formalin apparatus
where movement of the formalin injected paw is monitored and the
number of paw flinches tallied by minute over the next 60 minutes
(Malmberg, A. B., et al., Anesthesiology (1993) 79:270-281).
[0150] Results can be presented as Maximum Possible Effect SEM,
where saline control=100%.
EXAMPLE 17
Spinal Nerve Ligation Model of Neuropathic Pain
[0151] Spinal nerve ligation (SNL) injury can be induced using the
procedure of Kim and Chung, (Kim, S. H., et al., Pain (1992)
50:355-363) in male Sprague-Dawley rats (Harlan; Indianapolis,
Ind.) weighing 200 to 300 grams. Anesthesia is induced with 2%
halothane in O.sub.2 at 2 L/min and maintained with 0.5% halothane
in O.sub.2. After surgical preparation of the rats and exposure of
the dorsal vertebral column from L.sub.4 to S.sub.2, the L.sub.5
and L.sub.6 spinal nerves are tightly ligated distal to the dorsal
root ganglion using 4-0 silk suture. The incision is closed, and
the animals are allowed to recover for 5 days. Rats that exhibit
motor deficiency (such as paw-dragging) or failure to exhibit
subsequent tactile allodynia are excluded from further testing.
Sham control rats undergo the same operation and handling as the
experimental animals, but without SNL.
[0152] The assessment of tactile allodynia consists of measuring
the withdrawal threshold of the paw ipsilateral to the site of
nerve injury in response to probing with a series of calibrated von
Frey filaments. Each filament is applied perpendicularly to the
plantar surface of the ligated paw of rats kept in suspended
wire-mesh cages. Measurements are taken before and after
administration of drug or vehicle. Withdrawal threshold is
determined by sequentially increasing and decreasing the stimulus
strength ("up and down" method), analyzed using a Dixon
non-parametric test (Chaplan S. R., et al., J Pharmacol Exp Ther
(1994) 269:1117-1123), and expressed as the mean withdrawal
threshold.
[0153] The method of Hargreaves and colleagues (Hargreaves, K., et
al., Pain (1988) 32:77-8) can be employed to assess paw-withdrawal
latency to a thermal nociceptive stimulus. Rats are allowed to
acclimate within a plexiglas enclosure on a clear glass plate
maintained at 30.degree. C. A radiant heat source (i.e., high
intensity projector lamp) is then activated with a timer and
focused onto the plantar surface of the affected paw of
nerve-injured or carrageenan-injected rats. Paw-withdrawal latency
can be determined by a photocell that halted both lamp and timer
when the paw is withdrawn. The latency to withdrawal of the paw
from the radiant heat source is determined prior to carrageenan or
L5/L5 SNL, 3 hours after carrageenan or 7 days after L5/L6 SNL but
before drug and after drug administration. A maximal cut-off of 40
seconds is employed to prevent tissue damage. Paw withdrawal
latencies can be thus determined to the nearest 0.1 second.
Reversal of thermal hyperalgesia is indicated by a return of the
paw withdrawal latencies to the pre-treatment baseline latencies
(i.e., 21 seconds). Anti nociception is indicated by a significant
(p<0.05) increase in paw withdrawal latency above this baseline.
Data is converted to % anti hyperalgesia or % anti nociception by
the formula: (100.times.(test latency-baseline
latency)/(cut-off-baseline latency) where cut-off is 21 seconds for
determining anti hyperalgesia and 40 seconds for determining anti
nociception.
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